Zbornik gozdarstva in lesarstva, 39, 1992, s. 133 - 172 
FDC: 176.1 Quercus robur L., Q. petraea (Mattuschka) Liebl., Q. pubescens Willd., Q. cerris L.: 
164,5 + 164,7 (497.12) 
THE IMPORTANCE OF MORPHOLOGICAL CHARACTERISTICS 
FOR IDENTIFICATION OF OAK SPECIES 
Ivan SMOLE*, Franc BATIČ** 
Abstract 
Taxonomical variability of herborized samples of four oak species from a preliminary 
examination is discussed in the paper. Stress is laid on statistical processing of 
morphological eharacter.istics of oaks. 800 ]eaf samples of four oak speeies 
(pedunculate oak, sessile oak, pubescent oak, turkey oak) and 395 acorn samples 
(pedunculate oak, sessile oak, pubescent oak) from the whole territory of Slovenia 
were examined. It was found that the typical morphological characteristics (shape 
and dimensions of leaf lamina, length of petioles and fruit-stalks) are important 
especially for distinguishing oak species and that they also have an important role in 
intraspecific classification. No relationship or interdependence of these signs to other 
morphological characteristics - the trichomes, for example - or to the characteristics 
of acorns were noticed. 
Key words: pedunculate oak (Quercus robur L.), sessile oak (Q. petrea (Mattuschka) 
Liebl.), pubescent oak (Q. pubescens Willd.), turkey oak (Q. cerris L.), herba-
rium samples, morphological characte., leaf, fruit, pure species, variety, hybrid 
POMEN MORFOLOŠKIH ZNAKOV PRI DOLOČANJU HRASTOVIH 
VRST 
Izvleček 
Delo vsebuje taksonomsko obravnavo herbarijskih vzorcev štirih hrastovih vrst iz 
predhodne raziskave s poudarkom na statistični obdelavi morfoloških znakov. 
Obdelano je bilo 800 listnih vzorcev ( doba, gradna, puhastega hrasta in cera) in 395 
vzorcev želoda (doba, gradna in puhastega hrasta) iz vse Slovenije. Ugotovljeno je, 
da so tipični morfološki znaki (oblika in dimenzije listne ploskve, dolžina listnega in 
plodnega peclja) pomembni predvsem za razločevanje hrastovih vrst in da imajo pri 
notranjem členjenju specifično vlogo, ni pa ugotovljena večja zakonitost povezave ali 
soodvisnosti med temi znaki in morfološkimi znaki kot so listni laski ali trihomi in 
lastnosti želoda. 
Ključne besede: dob (Quercu.s robur L), graden (Q. petraea (Mattuschka) Liebl.), 
puhasti hrast (Q. pubescen.s Willd.), cer (Q. cerris L.), herbarijski 
vzorci, morfološki znak, list, plod, čista vrsta, različica, križanec 
I. S. Dipl. Ing. of Forestry, Inštitut za gozdno in lesno gospodarstvo, Večna pot 2, 61000 Ljubljana, Slovenija 
Prof. Dr. F. B. DipL Biol.; Inštitut za gozdno in lesno gospodarstvo, Večna pol 2. 61000 Ljubljana, Slovenija 
Zbornik gozdarstva in lesarstva, 39 
CONTENTS 
1 INTRODUCTiON 135 
2 METHODS 136 
3 RESULTS 141 
3.1 Corrections and additions to the primary identification of species 141 
3.2 Teritorrial dispersion of sample trees of pedunculate oak and 148 
sessile oak and their varieties 
3.3 Results of statistical analysis of morphological characteristics of 148 
leaf samples 
3.4 Results of statistical analysis of oak fruits 155 
4 DISCUSSION 164 
5 CONCLUSION 165 
6 RESUME 166 
7 REFERENCES 167 
134 
. Smole I., Batič F., The importance of morphological.. 
1 INTRODUCTION 
The study of the morphological characteristics of oaks and evaluation of their 
importance for oak-species identification on our institute started in October 1990, 
when - within Slovene-Austrian research cooperation - oak sampling was carried out 
on 32 typical oak sites throughout Slovenia. The leaves were collected from 160 trees 
and the acorns from 93 trees of the same populations. 
The results of the analysis of leaf samples (characteristics according to a key) have 
already been presented in the yearly report on the Austro-Slovene research 
cooperation (SMOLE 1991). It was cited in the report that among the 160 sample 
trees, there were 71 trees of pedunculate oak, 66 trees of sessile oak, 12 of turkey 
oak and 11 of pubescent oak. Por the identification of species, the descriptions of 
morphological characteristics of leaves and acorns (RECHINGER 1957-1958, HESS 
et al. 1976) were applied. Measurable morphological characteristics visible with the 
naked eye (the shape, dimensions and other properties of different leaf parts) and 
characteristics visible only under a certain magnification (the shape and distribution 
of trichomes on various leaf parts, which differ significantly among oak species) were 
examined. 
On some samples of pedunculate oak and sessile oak, significant deviations of micro-
characteristics from characteristics declared significant for these two species in the 
above-mentioned literature were noticed. We therefore assumed that these samples 
belonged to mixed species or hybrids, while samples without any unusual 
characteristics belonged to pure species. According to this hypothesis, the 160 trees 
were classified into the following groups: 
- pedunculate oak with no unusual characteristics 
- pedunculate oak hybrids (pedunculate oak : turkey oak) 
- pedunculate oak hybrids (pedunculate oak : sessile oak) 
- sessile oak with no unusual characteristics 
- sessile oak hybrids (sessile oak:turkey oak,sessile oak:pubescent oak) 
37 trees 
31 trees 
3 trees 
11 trees 
55 trees 
No variability in hairiness of different leaf parts was noticed in pubescent oak and 
turkey oak, so these two species were considered to be pure. 
Intraspecific classification showed that with pedunculate oak, the proportion of 
nonhybridized individuals was almost equal to that of hybrids, while with sessile oak, 
there were five times more hybrids than trees of the pure species. It could therefore 
be deduced that in Slovenia, sessile oak is much more liable to crossbreeding with 
other species of oaks than pedunculate oak. It was further noticed that with hybrids 
of both oak species, the morphological characteristics of turkey oak prevailed (the 
shape of leaves, for example ), and that with hybrids of sessile oak, the influence of 
pubescent oak was also possible - especially in thc regions of the Karst, Slovenc 
Primorje and Istra. 
135 
Zbornik gozdarstva in lesarstva, 39 
In this phase of the. investigation, acorn samples were not analysed. 
The first results of the investigation and the extensive herbarium collection required 
further work in order to find the relationship between typical eharaeteristics of the 
Ieaf lamina (shape and dimensions) and trichomes as possible characteristics of 
species, and also to evaluate their importance for identification of oak species and 
their varieties. The findings of this investigation are presented in the article. 
2 METHODS 
In the first phase of the investigation, the following working procedure was used: 
Ali oak species were sampled at their native sites, defined by the principles of 
the Central European School for vegetation studies. Not only the sites in 
which oaks were the main element of forest plant assoeiations were included 
in the investigation, but also sites in whieh oaks were only mixed among other 
species of trees. 
Four of the most abundant oak species in Slovenia were chosen for the 
investigation: pedunculate oak (Quercus robur L.), sessile oak (Quercus petraea 
(Mattuschka) Leibl..), pubescent oak (Quercus pubescens Willd.), turkey oak 
(Quercus cerris L.). 
Sampling sites were chosen on the basis of vegetation and forest stand charts 
(review charts of native sites and plant associations), adapted after various 
sources especially for this purpose. 
On the basis of this information, 32 sampling sites were ehosen. On each site, 
from 5 trees chosen at random, the leafed twigs from the sunny side and the 
shady side of tree crowns were sampled for the herbariurn. The observations 
were recorded in a special questionnaire (Appendix 1 ). Fram the same trees 
if possible - acorns were also collected. 
For every ehosen tree, one twig with leaves from the sunny side and one from 
the shady side was herborized, altogether 320 samples. Signifieantly less fruits 
were sarnpled, and only the acorns from 79 trees were later applicable for ob-
servation. 
Triplets of leaf samples were collected and herborized - one of them was then 
sent to Austria, to the herbarium collection in Vienna, and the other two are 
kept in the forestry herbarium at IGLO. One of them is destined for the 
herbarium collection of the Department of Biology of the University of 
Ljubljana. 
A review of sampling plots (in relation to species of oaks and their territorial 
distribution) is presented in Table 1 and Figure 1. 
136 
Smole I., Batič F., The importance of morphological.. 
Appendix l.: Oak sarnpling in Slovenia 
QUERCUS ROBUR L. 
Place: Godešič by Škofja Loka 
Gaus-Krueser coordinates x: 5450.6 
y: 5114.1 
Quadrant: 9852/1 
Height above sea leve!: 400m 
Exposition: O 
lnclination: O 
Landscape type: FLAT LAND 
Relief: HILLY/BROKEN 
Plant association: QUERCO-LUZULO-FAGETUM 
Sampling site no.: 26 
Tree no. 1 
Date : October 15th, 1990 
Sampled by: E. Azarov 
I. Smole 
Bed-rock: diluvial clay 
Soil: pseudogley 
Description of the stand: uneven-aged in small areas, one-stratum stand, high forest 
Phase of development: polewood forest 
Complex: 0.8 
Tree measurements: - diameter: 29.0 
- height up to the crown: Srn 
Description of the tree: - at the edge of the forest 
predominated over 
- very vita) 
selfseeded 
well rooted 
- tree height: 12m 
Trunk: - inferior trunk, stout, one-axis, inclined, bent, twisted, 
thick-branched, few adventive shoots, few epiphytes 
Crown: strongly asymetrical, open, narrowed at two sides, 
few adventive shoots, few epiphites 
Fruit bear: - high 
Herbarium sample from: the crown periphery, tertiary branches at height of Srn 
137 
Zbornik gozdarstva in lesarstva, 39 
Table 1: Basic data on oak sampling in Slovenia in 1990 (Comment: The size of 
a sample series is 5 trees to a site) 
Succes. Date Sampling plot Oak species 
no. of 
the serie 
l. 27.9.90 LJUBLJANSKO BARJE, Rakova jelša, 
28.9.90 Zgornji Log, along the main road and side roads Quercus robur 
2. 1.10.90 PRAGERSKO, Zgornja gorica, Grajevnik, along the forest road Q. robur 
3. 1.10.90 SREDIŠČE OB DRAVI, Obrež, V. Krče, along the local road, at the edge of Q. robur 
the forest 
4. 2.10.90 DOBROVA PRI LJUBLJANI, thc mountain riclge abovc thc local road Q.petraea 
5. 2.10.90 TOŠKO ČELO, Prevalnik, the mountain ridge, by the monument to the Q. petraea 
partisans Q. robur 
6. 3.10.90 LJUTOMER, Ključarovci, Ključarovski gozd, at thc eclge of thc village Q. robur 
7. 3.10.90 MURSKA ŠUMA, the local roacl crossing, soulh of Lcdava Q. robur 
8. 3.10.90 ČRNI LOG, Banuta, al the shore of the arlificial pond Q. robur 
9. 4.10.90 KRAKOVSKI GOZD, Gmajna, along the local road Gmajna· Zameško Q. robur 
10. 4.10.90 KRAKOVSKI GOZD, Koprivnik, along the strcam of Lokavec, the edge of Q. robur 
the forest 
11. 4.10.90 KOSTANJEVICA, M. Vodenice, M. Ban, along the local and the forest road Q. petraea 
12. 8.10.90 BELA KRAJINA, Vranoviči, along the local road Metlika - Črnomelj Q. robur 
13. 8.10.90 BELA KRAJINA, Stara Lipa pri Vinici, the edge of the pasture-overgrowing Q. robur 
14. 8.10.90 BELA KRAJINA, Razvaje by Damelj, along the local road Vinica-Stari trg Q. cerris 
15. 9.10.90 DIVAČA, at the foot of the hill of Kožlck, along the local road Divača - Q. pubescens 
Lokev 
16. 9.10.90 DIVAČA, at the foot of the hill of Kožlck, along the local road Divača - Q. cerris 
Lokev and along the railway 
17. 9.10.90 BRKINI, Ostrožno brdo, Boršt, the hi II-slope ahovc thc forcst road Q. petraea 
(Ljubljanska cesta) 
18. 10.10.90 NOVA GORICA, Panovce, the ridge south to the forest study way Q.petraea 
19. 10.10.90 NOVA GORICA, Stara gora, Strmec, along the local riclge road Q. petraea 
20. 10.10.90 COL, below the village, above the local road Ajdovščina - Col Q. pubescens 
138 
(5x) 
(5x) 
(5x) 
(5x) 
(4x) 
(lx) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
(5x) 
Smole l., Batič F., The importance of morphological.. 
Succes. Date Sampling plot Oak spedes 
no. of 
the serie 
21. 11.10.90 ISTRA, Čela, the hill by the local road Gračišče • Pridvor Q.petraea (5x) 
22. 11.10.90 ISTRA, Labor, Peskovlje, along the local ridge road Labor • Boršt Q. pubesce11s (Sx) 
23. 11.10.90 ISTRA, Cerje by Župančiči, the hill above the valley of Piojevec Q.petraeo (2x) 
Q. cenis (2x) 
Q. pubescens (lx) 
24. 15.10.90 GORENJSKA, Črnivec by Brezje, along the forest road Črnivec ~Dvorska vas Q.pclraea (Sx) 
25. 15.10.90 GORENJSKA, Rodine by Begunje, the remainder of the fronta! moraine Q. robur (Sx) 
below the village 
26. 15.10.90 SORŠKO POLJE, Godešič by Reteče, along the railway and the lines man's Q, robur (Sx) 
cabin 
27. 16.10.90 SELšKA DOLINA, Podlonk by Žclewiki, forest cdgc at thc foot o/ the hill of Q. petraea (Sx) 
1.onk 
28. 16.10.90 POLJANSKA DOLINA, Hlavče njive, the ridgc abovc the village Q. petraeo (5x) 
29. 16.10.90 ŽIROVSKI VRH, Zadobje by Lučine, the hill above the village Q,petraea (Sx) 
30. 17.10.90 POSAVSKO HRIBOVJE, Velika Preska by Polšnik, the hill above the village Q. petraea (Sx} 
31. 17.10.90 CELJSKA KOTLINA, Lopata by Medlog, thc forcst behind the new village Q. robur (5x) 
32. 17.10.90 TOPOl.ŠICA BY ŠOŠTANJ, Sv. Jakob, the hill behind thc church Q. robur (5x) 
Number Number Number of Numbcr Q. robur: 71x 
of series: of days: sampling sites: of sample Q. petroea: 61x 
trees: Q. cerri:;: 12x 
Q. pubescens: 16x 
32 13 32 Total: 160x 
Comment: The propertions of trees of different species in the table are corrected 
(with regard to the original classification • see Chapter 3.1) 
In the second phase of the investigation, the primary identification of oaks was 
completed by analysis of a larger number of leaf samples. The measurable 
morphological characteristics of the same samples were afterwards examined in order 
to find the relationship between the typical leaf lamina characteristics and the 
trichomes of the species under analysis. It was also our intention to verify the hy-
pothesis that the morphological characteristics of leaves growing on the sunny side of 
139 
Zbornik gozdarstva in lesarstva, 39 
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Figure 1: Review map of oak sampling sites in Slovenia for 1990 
140 
:) 
Smole I., Batič F., The importance of morphological.. 
a tree crown (first of ali the size of the leaf lamina) differ significantly from those of 
leaves from the shady side of a tree. 
For this purpose, 5 randomly chosen leaf samples were collected from each tree: 3 
samples from the sunny side and 2 from the shady side of the tree crown. The 
following parameters of each leaf were either measured or evaluated: length and 
width of leaf lamina, number of !obes at left and right side, length of petiole. Under 
stereomicroscope magnification of lOOx, the hairiness of the following parts of the 
leaves was evaluated: leaf lamina, veins and Ieaf margin on the upper and lower sur-
faces. A model of a questionnaire, modified to allow the data to be entered on a 
computer is shown in Appendix 2. Eight hundred leaf samples of pedunculate oak, 
sessile oak, turkey oak and pubescent oak were examined by this method, 
Measurements and evaluations of the morphological characteristics of oak fruits -
acorns - were also obtained if at least 5 applicable samples to a tree were available. 
The following morphological characteristics were cxamincd: number of fruits to a 
stalk, length of fruit stalk, length and width of fruit, typical shape of fruit, height and 
width of fruit cup (cupule), type of hairiness of the cupulc and the shape of its 
scales. An example of the questionnaire is given in Appendix 3. Three hundred and 
ninety five acorn samples of pedunculate oak, sessilc oak and pubescent oak were 
examined; the acorns of turkey oak were not collected because they ripen and fall in 
the second year after fruit-bear. 
3 RESULTS 
3.1 Corrections and additions to the primary identification of 
species 
Because of shortage of tirne in the first phase of the investigation it had been neces-
sary in the second phase to examine a larger number of leaf samples. The quantity of 
data now gathered allowed us to correct the primary identification of oaks. The same 
criteria as in the previous analysis were used. While in the preliminary investigation 
the deciding factors for oak classification were the morphological characteristics of 
leaf samples (shape and other characteristics of the leaf lamina, length of petiole, 
shape and persistencc of stipules), the varieties within individual species .in the sec-
ond phase were distinguished by observation and evaluation of the hairiness of leaf 
parts under stereomicroscope magnification. For the idcntification of samples, the 
morphological characteristics described in Slovenc and foreign literature were taken 
into consideration. 
According to MARTINČIČ and SUŠNIK (1984), the distinguishing characteristics 
are: 
Pedunculate oak: Leaves are obtusately pinnately !obed. Stlpules are membranous 
and shed early. Cupule scales are closely overlapping. Young shoots and 
petioles hairless or slightly hairy initially. Leaves hairless, rarely initially 
141 
Zbornik gozdarstva in lesarstva, 39 
slightly hairy on the lower surface. Leaves sessile or shortly petioled. Fruit 
stalk is half as short as the associated leaf. 
Sessile oak: In contrast to pedunculate oak, petioles are 2 - 4cm long. Fruits are 
sessile or with a very short common stalk. 
Pubescent oak: In contrast to pedunculate oak and sessile oak, the young shoots and 
leaves are hairy. Petioles are 10 - 15mm long. Leaf blades with 4 -7 obtuse 
lobes on each side. Cupule scales are closely overlapping. 
Turkey oak: Leaves deeply pinnately !obed, with pointedly sharpened !obes, hairy on 
the lower surface. Cupule scales protruding. Stipules thread-Jike, persistent. 
According to TRINAJSTIC (1988), the following features are characteristic of 
Quercus robur: 
Pedunculate oak: One-year old shoots are hairless. The torus (flower axis) is 
hairless, fruits are stalked. Leaves are entirely hairless, with a few simple hairs 
on the veins or leaf margins. 
DOMAC (1984) mentions the following characteristics as typical of the studied four 
species: 
Pedunculate oak: Lower surface of leaves is hairless, slightly hairy on the veins only. 
The fruit stalk is Iong, significantly longer than the petiole. The cupule is 
smooth, with short, roundish, closely overlapping, ringlike arrayed scales. 
Sessile oak: In contrast to pedunculate oak, its fruit stalk is very short, never longer 
from the petiole, or the fruits are sessile. Leaves are hairy on the lower 
surface, especially on the veins. 
Pubescent oak: Young branches are hairy. Leaves shallow !obed, densely hairy on 
the Jower surface. The fruit stalk is short, 1cm long at the most. Cupule scales 
are small, roundishly ovate, closely overlapping. 
Turkey oak: Leaves are pointedly !obed, hairy on the lower surface, the stipules 
persistent. Fruit scales are linear, protruding, curved. 
ROTHMALER (1988) defines oak species as follows: 
Pedunculate oak: Young branches and Jeaf buds hairless. The leaf )obes rounded, 
slightly heart-shaped at the base, bent downwards, the largest !obes towards 
the leaf apex. Petiole very short. Fruits stalky, ripen in the first year. 
Sessile oak: Young branches and buds are hairless. Leaf !obes are rounded, the base 
of the leaf lamina is wedge-shaped, fiat; the largest !obes are in the middle of 
the Ieaf hlade. Petiole is 1 • 3cm long. The fruits are sessile, ripen in the first 
year. 
Pubescent oak: Young branches and leaf buds stellately hairy. The leaf !obes are 
rounded; the lower Ieaf surface is covered with soft, long hair. The fruits ripen 
in the first year. 
Turkey oak: Leaves have 6 - 8 pointed Ieaf !obes. Both surfaces of young Ieaves are 
covered with grey hair and in old leaves, at least the lower surface - stellate 
hairs on the veins. The fruits ripen in the second year. 
142 
Smole l., Batič F., The importance of morphological.. 
The oak species are the most thoroughly described by RECHINGER (1957-58) and 
HESS et al. (1976). Their descriptions were combined in the following resume: 
Pedunculate oak: The leaves are wide wedge-like obovate, the widest above the 
middle or towards the apex in the upper third of Ieaf lamina. They are !obed, 
on every side with 5 - 6 obtuse to pointed !obes and unequal, wider or 
narrower obtuse and rnther deep indentations. The bottom lobe is often small 
and rounded, the second one already much greater, the third and the fourth 
often lingulately Iengthened and roughly irregularly toothed at the bottom. 
The upper !obes often egg-shaped and almost parnllel, ali - more often than 
not - rather widely rounded, on secondary shoots often distinctly pointed. 
Regarding the main rib, the Ieaves are often clearly asymmetrical. The Ieaf 
blades are 6 - 16cm Iong and 3 - 10cm wide. 
The interspaces between laterni veins - up to 7 on each side - are rnther wide. 
The veins are not distinctly parnllel and are oriented towards the Ieaf lamina 
indentations. The leaf lamina is rough, irregular, densely reticulate, in youth 
slightly silky hairy, later completely hairless, roughly to Ieathery membrnnous, 
shiny green on the upper surface, undefined, light green to blue-grny-green on 
the lower surface. The upper surface of leaves is hairless, the Iower with very 
few single simple hairs or hairless, never with stellate hairs (lOOx 
magnification). Petiole normally very short, 2-7mm Iong, rough, half-round, 
hairless. Stipules narrowly pointed and very unpersistent. 
The fruits are sessile, single or 2 - 5 on a hairless or seldom slightly hairy 
stalk, which is about half as long as the subtending leaf, sometimes shorter or 
longer. The fruit is oblongly ovoid, pointed, 18 - 28mm long, 7 - 15mm broad, 
with the lower fourth or third, rnrely up to a half, enclosed in the fruit cup 
(cupule). 
The cupule is 8 - 12mm high, and of a diamctcr of 7 - 14mm; with tender, 
silky, egg-shaped, closely ovarlapping scales, the margins of which are 
distinctly grown together and thus form spirnlly twisted girdles, ending above 
with more or Iess hairless and not overgrown curled edges. 
Sessile oak: The leaves are widely obovate to elliptically lanceolate, the widest in the 
middle or towards the apex, the base is shortly wedge-like narrowed or 
lengthened towards petiole, seldom rounded or cordate, earless, widely 
rounded or narrowed towards the apex. They are !obed, with 5 - 8 (or 10) 
rounded, smooth-edged !obes on each side (the bottom 1 - 2 !obes are 
sometimes toothed), and short, wide to narrow indcntations, which are either 
shallow or stretch approximately to a fourth of the leaf lamina width. The 
leaves are 8 - 12 (16)cm long and 5 - 7 (lO)cm widc. 
Laterni veins, which split from the mid-vein at an acute or right angle, often 
Iead only towards the !obes and not towards indentations. The intermediary 
venation is irregular, roughly meshy, sparse and inconspicuous. The upper 
surface of the leaf lamina is green, slightly shiny, the Iower surface of a lighter 
143 
Zbornik gozdarstva in lesarstva, 39 
colour, overgrown with sessile, stellate hairs, the points of which are not 
longer than 0.2mm (100x magnification). In youth, sometimes a few simple 
silky hairs are also present on the veins, which la ter. become hairless and 
remain hairy only in the vein axillas. The petiole is often conspicuously 
grooved, 12 - 24mm long, hairless. The stipules are drily membranous, hairless 
or hairy, shed early. 
The fruits are sessile or on a common, up to 15 (20)mm long stalk in the leaf 
axillas, single or up to 5, seldom more. The fruit cup (cupule) is 6 - 12mm 
high, 8 - 14mm wide, with a thin shell and small, ovately lanceolate, pointed, 
at the back densely fuzzy hairy, slightly convex (never protruberantly knobby), 
closely overlapping scales. The fruits are ovoid, often distinctively pointed, 16 
- 26mm long, 8 14mm wide. 
Pubescent oak: The leaves are similar in shape to the leaves of pedunculate oak, 
they are obovate to oblongly obovate, only sometimes eared, often the widest 
in the middle. At the base they are narrowly wedge-like or cordate and obtuse 
at the apex. On both sides they have 4 - 7 (8) often shortly rounded !obes, 
which are curled under at the top. The Iobes sometimes have a small point, 
with rather shallow and widely wavy rounded, seldom deeper and narrow 
indentations between them. The leaves are 5 - 8 (l0)cm long and 4 - 6cm 
wide. 
Lateral veins only go to the !obes and not to indentations. The leaf lamina is 
densely felty in spring, later pale green, fuzzy or whitely felty, at the end 
sometimes almost completely hairless. The lower surface of leaves is 
sometimes thickly covered with sessile, mostly 4 - 6 part stellate or bushy 
hairs, the points of which are mostly 0.3 - 0.6mm long. 
The petiole is shorter than 2cm, often up to 1cm long, felty, covered with 
stellate hairs. It is shorter on the short shoots, the leaves are often sessile. 
The stipules are spade-like, linearly lanceolate, hairy at the apex, unpersistent, 
only on the secondary shoots more persistent. 
The groups of 1 5 fruits, are almost sessile or shortly stalked. The fruits are 
smaller and slender than with pedunculate oak and sessile oak, oblong and 
smooth, pointed. The cupule is semicircularly cup-shaped and embraces the 
fruit to about one third or one half; it has various, brick-like arrayed, closely 
overlapping, thickly felty scales. The lower ones are a little wider and have 
clipped tip, the middle and the upper ones are triangularly pointed. The 
uppermost are narrowly lanceolate and shorter than the others. 
Turkey oak: The Ieaves are oval in their outline, narrowly oblong to oblongly 
obovate, irregularly and usually deeply !obed ( often almost to the main rib), 
seldom only lobedly toothed, normally with 4 - 9 triangular, smooth-edged or 
toothed (with 1 - 4 teeth) !obes on each side, which have short fringed points 
on top (1mm long at the most). The leaves are 3 - 15 (18)cm long and 2 - 9 
144 
Smole I., Batič F., The importance of morphological.. 
(12)cm wide. The ratio between their length and width is approximately 2,5:L 
Lateral veins seldom go to indentations. In youth, the leaves are yellowishly 
stellately hairy on both surfaces, later almost hairless, somewhat paler green, 
membraneous leathery and very rough on both surfaces, brown to yellowish 
brown in autumn. On the upper surface they are dispersely and on the lower 
surface densely hairy, covered with sessile, mostly 6 - 10 part stcllate hairs, 
because of which the lowcr surface is gray green. The hair points are normally 
not longer than 0.3mm. 
Thc petiole is up to 2.5cm long. The stipulcs are linearly lanceolate or linear, 
protruding, felty hairy and do not shed even on the fallen leaves. 
The fruits ripen in the second autumn. They are single or 2 - 4 to a short or 
longer, up to 27mm long stalk. The fruit is ovoidly oblong, slightly bigger than 
with pedunculate oak, up to 3cm long, brown, felty hairy in the upper part, 
elsewhere hairless. The fruit cup is bigger than with pedunculate oak, it 
ernbraces the acorn approximately to one third or one half. It is covered by 
linearly pointed, brown, felty scales, the lower of which have protruding 
processes, while the middle and the upper ones fold obliquely outwards 
immediately above their base and thus protrude almost to the whole length of 
the cupule. 
Beaving in mind to the described morphological charactcristics and hairiness of 
various leaf parts, the leaf samples were classified anew. It should be mentioned that 
the hairiness of leaf parts was only evaluated, and the length of trichomcs and their 
points was not measured. The classification is presented in Table 2. 
From the table below it can be scen that the primary identification of species was 
changed - in the case of pedunculate oak, the numbcr of trees of the pure species is 
smaller, while thc number of trees which are considered to be varieties or hybrids of 
the same species is much greater. The number of trees of sessile oak decreased, but 
the ratio between pure and hybrid trees remained almost unchanged. With pubesccnt 
oak, thc number of trecs increased proportionally to the decrease in the number of 
sessile oak. The reexamination of sampled material showed that some trees of 
pubescent oak species were falsely identified in the primary analysis as trees of 
sessile oak, with some characteristics unus,ual for this species. 
The number of samples identified as turkey oak remained the same as before. 
145 
Zbornik gozdarstva in lesarstva, 39 
Table 2: Classification of sample trees according to the type of leaf hairiness 
Oak species Classification of leaf samples in relation to the Together 
hairiness of different leaf parts 
Number Propertion of 
of trees trees in % 
Quercus robur Samples with characteristics typical of the species 31 19 
Q. robur* Samples with unusual characteristics 40 25 
Q.petraea Samples with characteristics typical of the species 10 6 
Q. petraea* Samples with unusual characteristics 51 32 
Q. pubesce11s Samples with characteristics typical of lhe species 16 10 
Q. cerris Samples with characteristics typical of the species 12 8 
Tota! 160 100 
* An accurate classification of the samples by this criterion is presented in Table 3 
and Table 4. 
Another aim of the thorough analysis of lcaf samples was an accurate classification 
of individuals of pedunculate oak and sessile oak according to the specific hairiness 
of their leaf parts. The results are presented in the following table. 
Table 3: Classification of pedunculate oaks according to thc type of hairiness of their 
leaf parts 
Oak species Different types of hairi11ess of the leaf samples Number Propertion of 
of trees trees in% 
Quercus robur The upper surface of leaves hairless, the lower surface 31 44 
with simple hairs 
Q. robu:r 1 Stellate hairs on the veins of the upper surface of leaves* 30 43 
Q. robur 2 Stellate hairs on the veins of the lower surface of leaves 1 1 
Q. robur 3 Stellate hairs on the upper surface of leavcs 1 1 
Q. robur 4 Stellate hairs on the vei11s and the lower surface of leaves 2 3 
Q. robur 5 Stellate hairs 011 the veins of the upper a11d the lower 3 4 
surface of leaves 
IQ .. robur 6 Stellate hairs 011 the vei11s of the upper surface a11d 011 3 4 
the entire lower surface of leaves 
:rotal 71 100 
* Note: The lower surfaee of leaves of all the varieties ofpedunculate oak is 
normally eovered with dispersely arrayed, simple hairs, as with the pure species, in 
addition to other hairs mentioned. 
146 
Smole I., Batič F., The importance of morphological.. 
The table above shows that the number of pedunculate oak hybrids exceeds the 
number of trees of pure species, but only. the first of the varieties is abundant. It 
should also mentioned that ali the composed hairs (with 2 - 6 or more points) were 
considered stellate hairs. Among the samples of pedunculate oak, there were many 
specimens with 2 - part, fork-like hairs absolutely predominating, among which no 
more-part hairs were found, even by examination of the complete sample from an 
individual tree. There is unfortunately no information or explanation in the available 
literature of such mutilated morphological characteristics. 
In the case of sessile oak, the number of diverse varieties is much lower than with 
pedunculate oak. The results of the analysis are shown in Table 4. 
Table 4: Classification of sessile oak trees according to the type of hairiness of the 
leaf parts 
Oak species Different types of hairiness of the leaf samples Number Proportion 
of trees of trees in % 
Quercus petraea The upper surface of leaves hairless, the lower surface 10 
with stel!ate hairs 
Q. petraea 1 Stel!ate hairs on the veins of the uppcr surface of 40 
leaves* 
Q. petraea 3 • • Stellate hairs on the veins and the upper surface of 10 
leaves 
Q. petraea 6 Stellate hairs on tile veins of the upper surface, 1 
simple hairs on the lower surface of the leaves 
Tota! 61 
* Note: The lower surface of leaves of sessile oak varieties as with the pure 
species - is covered with stellate hairs. 
16 
66 
16 
2 
100 
** Note: The varieties of sessile oak are numbered in the same way as varieties of 
pedunculate oak with regard to the trichome position on the leaves 
The number of varieties (hypothetical hybrids) of sessile oak greatly exceeds the 
number of pure species trees, .but only two of the varieties are more abundant. In 
this case, too questionable 2-part or fork-like hairs were included among the stellate 
hairs. An assumption was also made that the upper surface of leaves of this species 
is glabrous, although in the literature this is not additionally emphasized (as for 
example in the case of pedunculate oak). 
A hypothesis exists that ali deviations from the characteristical morphologic features 
of an oak species are signs of the influence of some other oak species. Assuming this 
hypothesis, the examined samples of pedunculate oak and sessile oak most frequently 
show the influence of turkey oak and pubescent oak, because only in these two spe-
cies is the upper leaf surface stellately hairy. 
147 
Zbornik gozdarstva in lesarstva, 39 
A delimitation of their influence would probably only be possible by measuring the 
hair dimensions, although this was not done in our analysis. In the case of inter 
influence, sessile oak affects the features of pedunculate oak more frequently than 
vice versa, but such effects could only be found in a small number of samples. 
3.2 Teritorrial dispersion of sample trees of pedunculate oak and 
sessile oak and their varieties 
By mapping the territorial dispersion of sample trees we tried to discover whether 
any rules exist for the spread of individuals of pure species and their varieties. An 
understanding of this would make it possible to delimit the areas of major external 
influence from areas in which the influence is smaller or does not exist at ali. Only 
sample plots in which ali 5 trees were of the same oak species were taken into 
consideration. 
In the case of pedunculate oak, the trees from 14 sampling plots were examined. It 
was discovered that on one sample plot all 5 trees belonged to the pure species, 
while on other sample plots, typical pedunculate oaks and varieties were mixed in 
different proportions. To make at least a rough territorial division, we decided on a 
compromise - so sample plots with at least three typical species trees were 
considered to be areas of low influence and sites with at least three hybrid trees 
were considered to be those greater influence. According to this criterion, 2 growing 
sites of pedunculate oak in Prekmurje, 1 growing site on Mursko polje, 1 in 
Krakovski gozd and 2 in Bela Krajina - ali in the eastern part of Slovenia - were 
defined as areas of low influence. Large influence was found at 3 localities in the 
Ljubljana basin and 5 in eastern Slovenia - one of the sitcs surprisingly lying in 
Krakovski gozd, the largest continuous area of pedunculate oak in Slovenia. Ali the 
mentioned sites are presented in Figure 2. · 
The territorial dispersion of 11 growing sites of sessile oak showed that only one in 
the surroundings of Ljubljana could be considered a site of low influence, while all 
the other 10 sites, dispersed from thc westernmost borders of Slovenia - from Istra 
and Nova Gorica over Brkini, Žirovski vrh, Selška and Poljanska dolina, Ljubljana 
basin and the Sava hills to the foothills of the Gorjanci and to Kostanjevica in the 
east - are places of large external influence, where varieties predominate over typical 
sessile oaks. The site dispersion is presented in Figure 3. 
3.3 Results of statistical analysis of morphol<>gical characteristics 
of leaf samples 
The visible morphological characteristics, which could be measured ot at least 
evaluated (the frequency of their occurance, for example), were included in statistical 
analysis. First of ali, the degrec of uncertainty was calculated by the T-test. An cval-
148 
Smole l., Batič F., The importance of morphological.. 
uation of the significant differences of the given values was thus rnade possible. In 
cases in which such calculations would not be appropriate, reciprocal tabular 
intercomparisons of thc desired parameters or phenomena were carried out. The 
following more important results were obtained: 
The degree of uncertainty estimates (madc with the T-test) showed that no 
significant morphological differences existed between leaves from the sunny 
side and Ieaves frorn the shady side of a tree. The calculation is valid for ali 
samples and ali species of oaks, with the exception of one morphological char-
acteristic in the fourth variety of pedunculate oak. In further analysis, the 
latter deviation was ignored, so ali the leaf samples of a tree were treated as 
a homogeneous calculation sample. The results. of the mentioned analysis are 
listed in the following summary table. 
Table 5: Degree of uncertainty (T-test)' for significant differences between leaves 
from sunny side and the leaves frorn the shady side of the tree crown 
Oak species Number of !obes Lcaf dimcnsions Pctiole length 
right side left side length width 
Quercus robur 0,572 0,745 0,610 0,932 
Quercus robur 1 0,736 0,721 0,339 0,515 
Quercus robur 2 0,596 0,789 0,666 0,524 
Quercus robur 3 0,724 0,219 0,671 0,867 
Quercus robur 4 0,007 0,067 0,890 0,578 
Quercus robur 5 0,363 0,706 0,841 0,794 
Quercus robur 6 0;245 0,332 0,931 0,851 
Quercus petraea 0,765 0,728 0,830 0,910 
Quercus petraea 1 0,890 0,719 0,660 0,777 
Quercus petraea 3 0,858 0,665 0,477 0,640 
Quercus petraea 6 1,000 0,789 0,709 0,886 
Quercus pubescens 0,683 0,605 0,876 0,922 
Quercus cerris 0,818 0,605 0,296 0,131 
* Note: According to the theory of this calculation, the differences between the 
compared values are statistically significant when the degree of uncertainty is 
smaller than 0.05 (the uncettainty is below 5% ). 
0,370 
0,931 
0,870 
0,374 
0,326 
0,491 
0,852 
0,580 
0,570 
0,895 
0,663 
0,430 
0,981 
1 To simplify comment, the abbrevations from the computer analysis are used for different varieties 
and species 
149 
Zbornik gozdarstva in lesarstva, 39 
Table 6: Mean values for morphological characteristics of the chosen leaf samples 
Oak species Leaf dimensions Petiole length Number of !obes to a leaf 
(cm) 
length (cm) width (cm) left side right side 
Quercus robur 10,89548 6,61742 0,41290 5,5613 5,6645 
Quercus robur l 9,69200 5,99867 0,49333 5,2467 5,4067 
Quercus robur 2 8,50000 4,90000 0,38000 5,2000 5,0000 
Quercus robur 3 8,52000 5,38000 0,64000 5,8000 5,8000 
Quercus robur 4 11,88000 7,51000 0,54000 5,5000 5,6000 
Quercus robur 5 10,65333 6,59333 0,57333 5,4667 5,6667 
Quercus robur 6 10,86000 6,63333 0,54667 5,3333 5,6000 
Quercus petraea 10,38400 6,46400 1,77800 6,5800 6,7400 
Quercus petraea l 9,51700 5,91500 1,63000 6,3100 6,4450 
Quercus petraea 3 9,83800 6,42600 1,67000 6,4600 6,3600 
Quercus petraea 6 10,34000 5,50000 1,96000 5,6000 6,0000 
Quercus pubescens 7,55500 5,24500 1,23875 6,0125 6,1250 
Quercus cerris 10,84500 5,21333 1,29833 7,5000 7,2167 
Average - ali species 9,86313 6,04725 1,06313 5,9925 6,0813 
together 
The results of the calculation of the mean values of morphological 
characteristics of the studied oak species are shown in Table 6. The means for 
leaf dimensions and for leaf parts' number are presented because these two 
morphological characteristics are distinguishing signs for different species of 
oaks. In data processing, one has to bear in mind that the number of 
specimens to a species plays a decisive role in ali further calculations. For that 
reason the results are - at a first sight - often in contradiction to the 
statements in Table 6. 
The estimates of uncertainty with the T-test, made on the basis of the means 
for the morphological characteristics from TABLE 6, are presented in 
TABLE 7. The morphological characteristics of leaves of ali the four species 
of oaks vary among themselves most significantly. 
The leaves of turkey oak differ significantly in ali 5 parameters from the leaves of 
the first variety of pedunculate oak Rl' and from the Sl variety of sessile oak. In 
2 To simplify comment, the abbrevations from the computcr analysis are used for differcnt varieties 
and species 
150 
Smole I., Batič F., The importance of morphological.. 
four parameters - with the exception of thc leaf lamina lcngth - they vary 
significantly from the Ieaves of typical pcdunculatc oak samples and of three 
varieties of this species - R4, RS and R6 - and from the varicty S3 of sessilc oak. 
From the samples of other oak species (pure species and varieties), the leavcs of 
turkey oak diffcr significantly in at lcast two morphological featurcs. 
The lcaf samples of pubescent oak diffcr significantly in ali S characteristics from the 
leaves of pure pedunculate oak and sessile oak and their varieties Rl and Sl. From 
ali other samples, thcy differ at Jeast in the length of thc pctiole. 
The leavcs of pure pedunculate oak differ in ali S morphological characteristics from 
the leaves of the variety Sl of sessile oak. From other samples, they vary in 1 - 4 
features. The most frequent differences between the leaves of pedunculate oak and 
sessile oak are the differences in the length of the petiole. Differences in leaf 
lobeness are less frequent, and the fewest diffcrcnccs betwcen the two species and 
thcir varieties occur in the length and width of leaf lamina. In this comparison, the 
most interesting variety is certainly the sessile oak variety S6, which only differs 
significantly from ali the varieties of pedunculatc oak in thc pctiolc length, while dif-
ferences in ali the other morphological characteristics are not significant. 
Much more important than the differences among leaf samplcs of the studied four 
species are the morphological diffcrences within the same species. Attention should 
therefore be paid to the following statistical results: 
With pedunculate oak, the only significant difference was noted between the leaves 
of typical peduneulate oak and the leaves of thc most abundant variety Rl. The leaf 
samples vary in 4 morphological characteristics: in lcngth and width of the leaf 
lamina, in length of the petiole and in the number of !obes on thc lcft side of a leaf. 
In addition the estimate of uncertainty made for the number of Iobes on the right 
side of the leaves only slightly exceeds thc permittcd degree of uncertainty, with a 
value of 0,054 (see Table 7). 
In ali other cases, differcnces among pedunculate oak specimens are only significant 
in some characteristics. The leaves of pedunculate oak varieties R3, RS and R6, for 
example, only vary from the typical individuals of this species in the length of 
petiole, and the significant difference hetween the lcaf samples of varieties Rl and 
R4 is only the length and width of the leaf lamina. 
Because of the established significant differences in the population of pedunculate 
oak samples, an additional tabular comparison of hairiness of the lower surface of 
leaves of this species was performed. It is presented in Table 8. 
151 
Zbornik gozdarstva in lesarstva, 39 
Table 7: T-test calculations 
C p R Rl R2 R3 R4 R5 R6 s S1 S3 S6 
1--:, 000 illiii) :@r: '0011 1JID.(11 Q[i.97 flml ,055 C KD j..QQQ '. .Jl.QQ 1 ~: 1= 1 1 1 KL ; .JlQ.Q; 1 .Jl.QQ 1 000 ~ I.JlQ.QI I..QQQI l.fili.o, l.llOOI .00:Z : : 1 1 . 1 
LD :,ooo: 1 ,9161 013 i,084\ i,083; 1,3041 l,8211 \,986: 1,o91j ,712 
1 1 LS j,9071 1..QQQ! 007 1,707] 
1
,840: l.,QQ!I J.J!lil i,illl21 I...QQJI ,725 1 1 
PD ;,3.?71 11lQQ1 ..QQQ; \.lm: I.QQ.Q.t l.llOOI I.QQ.Q.1 j.,QQ!j ,iliJ2. 
p KD 003 JlTI ,522 \,167! ,145 ~937 p26~ ,806 
KL ,097 ,662 :,166\ ,068 ~I ~ ,388 
LD ,535 ,260 :.,_QQJ: .J!Q!i ~' ~I ,177 LS ,illlQ ,581 ,827 Lllli.: ,051 ~! 2 ~ ,674 
PD 000 .J1QQ .,QQQ i,000\ .,QQQ IJ!QQI 1.0001 .,QQQ 
R KD jJ)š"41 ,201 ,791 ,862 ,994 ,832 []ooj ,513 
KL ~I ,498 ,655 ,875 ,764 ,470 El ,942 ' . LD 1,0011 ,107 ,108 ,356 ,786 ,968 :,m: ~I ,709 LS 
1
,01sj ,089 ,218 ,220 ,968 ,979 \6651 ,,599j ,264 
PD l,!)fil 1 ,701 .,QQ2 ,280 ,035 ..Jli.Q_ L!lOO) .J!fil 
Rl KD ,457 ,467 ,622 ,420 ,547 ..QQQ ,274 
KL ,935 ,333 ,542 ,514 ,797 i~ .JlQ.Q ,533 
LD ,394 ,400 .,fil1 ,257 ,170 :,154: i,598: ,776 ,645 
LS ,273 ,535 ,038 ,323 ,286 i,189i [,725! ,241 ,616 
PD ,252 ,139 ,684 ,185 ,366 i,ooo! i.oooi ...llilll .Jl!l.4 
R2 KD ,308 ,419 ,291 ,324 :Jllii ..912 ~: ,233 
KL ,412 ,689 ,635 ,810 :.Qll: ,056 : 026! ,486 . : 
LD ,991 ,081 ,256 ,218 : 136i ., l ,466 . ,,394' ,425 
LS ,719 ,063 ,179 ,131 \,lll/ ,311 :161! ,624 
PD ,059 ,356 ,147 ,135 Looo: .,Qilil ~ .,illlQ 
R3 KD ,756 ,810 ,706 ,079 ,290 ,342 ,740 
KL ,689 ,553 ,404 ,151 ,378 ,237 ,724 
LD ,070 ,248 ,209 ,134 ,474 ,396 ,399 
LS ,112 ,321 ,258 ,263 ,592 ,331 ,916 
PD ,564 ,611 ,399 .Jl.QQ ..QQQ .JlQQ ..Q.Ql 
R4 KD ,891 1,00 Wlilli1 /,054/ ,090 ,550 
KL ,947 ,739 lm_ij Los3j .Jm ,884 
; : 
Wll$ LD ,405 ,490 :,1w ,083 ,433 
LS ,361 ,348 ,15'}, Lo2s1 ,183 ,117 
PD ,787 ,953 ~ 1.oo.d .JlQ.Q .!lilll. 
152 
Smole I., Batič F., The importance of morphological .. 
C p R Rl R2 R3 R4 RS R6 s Sl S3 S6 
R5 KD ,868 l,QQ2; ~ ,062 ,561 
KL ,731 Wl!ll Will Jill.5 ,793 
LD ,879 !,75~ j,1751 ,421 ,872 
LS ,962 ;,838j 125s ,808 ,357 
l oool 
!' : 
PD ,763 iJ!fil! ,illJ!! .QQ4 
R6 KD Wllll: JiiE 
: ' 
:,040'. ,467 
KL ;.Jlilil; L@A: :..Q.(g ,597 
:,110! 
: ' 
LD ',578i !,315: ,790 
LS '782' j,224: : 757' ,288 :• ; :' : 
PD !J!Q.[ [.Qooj :,ooo~ .QQ4 
s KD ,156 ,119 ,168 
KL ,174 ,607 ,065 
LD ,068 ,365 ,973 
LS ,112 ,931 ,313 
PD ,105 ,387 ,516 
Sl KD ,688 ,466 
KL ,452 ,217 
LD ,517 ,557 
LS ,148 ,677 
PD ,666 ,202 
S3 KD ,544 
KL ,116 
LD ,752 
LS ,385 
PD ,336 
KD number of lobes on right side C Quercus cerris 
KL number of lobes on left side p Quercus pubescens 
LD leaf Iength R Quercus robur 
LS petiol width s Quercus petraea 
PD length of petiol 
1 Stellulate trichomes on veins on upper leaf lamine side 
2 Stellulate trichomes on veins on lower leaf lamine side 
3 Stellulate trichomes on veins and on leaf lamine on lipper side 
4 Stellulate trichomes on veins and on leaf lamine on lower side 
5 Stellulate trichomes on veins on upper and lower side of Ieaves 
6 Stellulate trichomes on veins on upper lamine side and on the whole lower 
lamine side 
153 
Zbornik gozdarstva in lesarstva, 39 
Table 8: Comparison of hairiness of the lower surface of leaf lamina by samples 
of pedunculate oak 
Oak Position of leaf samples Type and density of hairs 
species 
o El E2 Zl Z2 
Quercus Sunny side Number of samples 91 4 
robur % of samples 95,8 4,2 
% of total no. of samples 60,7 80,0 
Shady side Number of samples 59 1 
% of samples 98,3 1,7 
% of total no. of samples 39,3 20,0 
Together Number of samples 150 5 
% of samples (%) 96,8 3,2 
Quercus Sunny side Number of samples l 88 3 
robur l % of samples 1,1 95,7 3,3 
% of total no. of samples 100 60,7 75,0 
Shady side Number of samples 57 1 
% of samples 98,3 1,7 
% of total 110. of samples 39,3 25,0 
Together Number of samples 1 145 4 
% of samples (%) 0,7 96,7 2,7 
Quercus Sunny side Number of samples 3 1 2 
robur 4 % of samples 50,0 16,7 33,3 
% of total 110. of samplcs 60,0 100 50,0 
Shady side Number of samples 2 2 
% of samples 50,0 l 50,0 
% of total 110. of samples 40,0 10,0 50,0 
Together Number of samples 5 1 4 
% of samples (%) 50,0 10,0 40,0 
Quercus Sunny side Number of samples 4 2 3 
robur 6 % of samples 44,4 22,2 33,3 
% of total no. of samples 57,1 40,0 100 
Shady side Number of samples 3 3 
% of samples 50,0 50,0 
% of total no. of samples 42,9 60,0 
Together Number of samples 7 5 3 
% of samples (%) 46,7 33,3 20 
Note: Ali leaf samples of the pedunculate oak varieties R2, R3 and RS are 
uniformly hairy El = 100% 
154 
~ 
95 
61,3 
60 
38,7 
155 
100 
92 
61,3 
58 
38,7 
150 
100 
6 
60,0 
4 
40,0 
10 
100 
9 
60,0 
6 
40,0 
15 
100 
Smole l., Batič F., The importance of morphological.. 
Key to other characters in the table: 
- Type of hairs: 
- Hair density: 
E - simple hairs 
Z - stellate hairs 
O - negligibly hairy or glabrous 
1 - single hairs 
2 - slightly hairy 
3 - averagely dense hairiness 
4 - densely hairy (pubescent) 
It can be seen from the table that typical samples of pedunculate oak and its variety 
Rl do not differ significantly in hairiness. The deviation is more evident in a com-
parison of varieties Rl and R6, in which leaf samples with simple hairs and leaf 
samples with stellate hairs on the lower side of the leaf hlade occur in a ratio of 
approximately 1:1. In the case of pedunculate oak varieties R2, R3 and RS, the 
hairiness of the lower surface of the leaves is entirely consistent with that of the pure 
pedunculate oak species. 
With sessile oak, within the spectrum of the visible and measurable characteristics of 
the leaves, the statistical analysis showed no significant differences between trees of 
the pure species and hybrid trees. As with pedunculate oak, a tabular comparison of 
hairiness of the Iower surfaces of leaves of this species was therefore performed. It is 
presented in Table 9. 
Irrespeetive of the slightly variable hair density, for ali three varieties of sessile oak, 
medium or average hairiness of the lower leaf surfaces is characteristic; this type of 
hairiness anyway is the most common with this oak species. No significant differences 
in this morphological feature existed among sessile oak specimens. 
3.4 Results of statistical analysis of oak fruits 
In the analysis of oak fruits, 395 samples were examined. Their classification to 
species is shown in Table 10. 
With pedunculate oak and pubescent oak, acorn samples were observed in addition 
to leaf samples in 62% of trees. The fruits of sessile oak were only analysed in 41 % 
of samples and in the case of turkey oak, no fruit samples were available. 
On average, 49% of the sample trees were included in the analysis of oak fruits. 
155 
- l 
! 
Zbornik gozdarstva in lesarstva, 39 
Table 9: Comparison of hairiness of the Iower surfaces of the leaf samples of sessile 
oak 
Oak Position of leaf samples Type and density of hairs 
species 
Z21 Z3 o El Zl Z4 E 
Quercus Sunny side Number of samples 4 4 19 3 30 
petraea % of samples 13,3 13,3 63,3 10,0 60,0 
% of total no. of samples 50,0 66,7 61,3 60,0 
Shady side Number of samples 4 2 12 2 20 
% of samples 20,0 10,0 60,0 10,0 40,0 
% of total no. of samplcs 50,0 33,3 38,7 40,0 
Together Number of samples 8 6 31 5 50 
% of samplcs (%) 16,0 12,0 62,0 10,0 100 
Quercus Sunny side Number of samples 1 16 27 78 122 
petraea % of samples 0,8 13,1 22,1 63,9 61,0 
1 % of total no. of samples 100 57,1 65,9 61,9 
Shady side Number of samples 1 12 14 48 3 78 
% of samples 1,3 15,4 17,9 61,5 3,8 39,0 
% of total no. of samples 100 42,9 34,1 38,1 100 
Together Number of samples 1 1 28 41 126 3 200 
% of samples (%) 0,5 0,5 14,0 20,5 63,0 1,5 100 
Quercus Sunny side Number of samples 3 4 20 3 30 
petraea % of samples 10,0 13,3 66,7 10,0 60,0 
3 % of totalno. of samples 100, 33,3 62,5 100 
Shady side Number of samples o 8 12 20 
% of samples 40,0 60,0 40,0 
% of total no. of samples 66,7 37,5 
Together Number of samples 3 12 32 3 50 
% of samples (%) 6,0 24,0 64 6,0 100 
Note: Foi- sessile oak variety S6, calculation was not possible, because of too few 
samples 
The statistical analysis began with a calculation of mean values for the morphological 
characteristics, which is presented in Table 11. 
On the basis of the mean values presented above, estimates for uncertainty with the 
T-test were made of the morphological characteristics for which such a statistical 
operation was reasonable. The following parameters were included in the calculation: 
number of fruits to a stalk, length of fruit stalk, length and width of a fruit and the 
height and width of the fruit cup ( cupule ). Ali other morphological characteristics of 
acorns were dealt with separately, in an individual way. The estimates of uncertainty 
with the T-test are shown in Table 12. 
156 
Smole I., Batič F., Thc importance of morphological.. 
Table 10: Presentation of the relation between the number of leaf samples and the 
number of acorn samples of different species 
Oak speeies Leaf sample Acorn samples Ratio Por-
leaves: tion 
Number Number Portion of Number Number Portion fruits fruits: 
of trees of speeies of trees of speeies of spe- leaves 
samples (%) (%) cies (%) 
Quercus robur 71 355 44 44 220 56 71:44 62 
Quercus 61 305 38 25 125 32 61:25 41 
petraea 
Quercus 16 80 10 10 50 12 16:10 62 
pubescens 
Quercus cerris 12 60 8 12:0 
Tota! 160 800 100 79 395 100 160:79 49 
Table 11: Mean values for the morphological characteristics of oak fruits 
Oak species No. of Stalk Fruit Fruit cup (cupule) 
fruits Jength 
to a (mm) length width typical height width hair scale 
stalk (mm) (mm) shape (mm) (mm) type shape 
Quercus robur 2,0714 47,2286 23,2643 13,1571 2,4143 7,4286 14,3429 1,0000 1,3571 
Quercus robur 1 1,8667 39,0667 21,2667 12,7833 1,7667 7,7667 14,0333 1,0000 1,5000 
Quercus robur 3 2,0000 28,0000 20,2000 12,8000 1,8000 7,0000 14,4000 1,0000 1,0000 
Quercus robur 5 2,4000 43,2000 24,0000 14,8000 1,0000 7,4000 16,6000 1,0000 1,0000 
Quercus robur 6 1,9000 46,1000 25,7000 14,8000 2,2000 8,0000 15,4000 1,0000 1,0000 
Quercus petraea 2,1333 6,7333 24,5333 13,0667 2,6000 8,7333 14,6000 1,0000 1,0000 
Quercus petraea 1 2,5333 2,9067 16,5733 10,7867 1,6400 7,4533 13,0667 1,0000 1,6667 
Quercus petraea 3 2,0667 2,6667 19,1333 10,8000 2,2000 7,1000 12,6000 1,0000 1,6667 
Quercus petraea 6 1,6000 5,6000 16,6000 12,6000 1,0000 9,0000 15,2000 1,0000 1,0000 
Quercus pubescens 1,5600 1,3600 20,0600 11,1400 2,4000 8,4600 13,0800 2,0000 3,9000 
Average (all spec.) 2,0582 25,9949 20,9671 12,2633 2,1089 7,6684 13,8380 1,1266 1,7468 
Note: No fruit samples were available for pedunculate oak varieties R2 and R4 
and for turkey oak 
157 
Zbornik gozdarstva in lesarstva, 39 
Table 12: Calculation of uncertainty by the T- te~t 
p R Rl R3 RS R6 s S1 S3 S6 
p STPL ]QQ ,058 ,262 lTu1j :,225i '02~ 'ooo: ..lli!1 i ,912! 
!.J!QQ! 
FI 
PED JlQQ .,QQQ ..® LllQQI i.,.QQ11 l..QQ.11 ,082 : .Jlilll.i 
PMD .JlQQ. ,220 ,929 iillj lmll ~: j 000[ ,305 : 034: ~· PMS JlQQ .,QQQ ,Q(IB lmi1 '.,ooQ! I.J!QQI ',215! ,433 :~, : i 
: ,519! CMV .,QQQ ,079 ,085 l,2011 :,mi 1,5921 ~; .JlQQ. 
CMS .,QQQ ...Q2.2. ,051 l,QQQ] ~ LQ21J :.~.Q~: ,139 i ,003: 
R STPL ,111 ,849 ,371 ,521 ,788 
~;;-i :: ,200 1...QQ.1.1 PED ...QQl .M2 ,100 ,873 .Jlilll. I.J!QQ.1 .QQQ 
PMD ..!!12 ,262 ,788 ,221 ,439 I.Jlllill :mi: ..fil.6_ 
PMS ,282 ,731 _,QQQ .m.o. ,883 1 oool ~: ,594 
CMV ,293 ,580 ,971 ,314 ...QQi 
1=1 
:,179! .M:.4 1,9171 
CMS ,448 ,955 .illill. ,146 ,673 l.ooo.1 :.000: ,400 
Rl STPL ,751 ,185 ,911 ,322 room ,293 ,506 
PED ,067 ,081 ,356 .Qilll I.Qillll .Jlilll. 000 
PMD ,424 ,365 ,050 ,082 1 oool ,077 ,123 
1=, 
PMS ,986 .Qilll ..lli!fi. ,628 1.illill.1 .Jlilll. ,851 
CMV ,446 ,715 ,754 .m.z l,3s4 1 ,056 ,222 
CMS ,773 .Qilll ,137 ,467 I 026I ,002 ,363 
R3 STPL ,524 ,857 ,825 ,287 ,872 ,524 
PED _mQ_ ,114 009 ..llilli .,ilil5 .Jill9 
PMD ,085 ,074 ,116 ,083 ,616 ,Q75 
PMS ..illl2. ,059 ,732 ..ill.9 .MB. ,829 
CMV ,524 ,305 ..fil.6. ,523 ,846 ,013 
CMS ,016 ,263 ,853 ,153 .Jl11. ,467 
RS STPL ,268 ,621 i,784, i,371; ,050 
i ooo\ ' PED ,697 _,QQQ : ooo: ..illlO. 
PMD ,578 ,847 i • .lli!l! i,mi Jllil. 
PMS ,.00 ..illl2. :.illlll: :.illlll! ,052 
CMV ,529 ,054 \,940j :,556: ; . .Jl22 
CMS ,128 Jfil ;,QQQj i,000: ,158 
R6 STPL _,586 \,oni i,5751 ,500 
PED ..!lilll. ;..illill.: :.lliill: ..llilll 
PMD ,627 ).lliilli ,J!.Qf ..llilli. 
PMS .ll21 i..lli!.Q! '.lliill: ,063 
CMV ,273 :,m: \,190: ,305 
CMS ,332 i,001i :.ooo! ,828 
158 
Smole l., Batič F., The importance of morphological.. 
p R Rl R3 RS R6 
s STPL 
PED 
PMD 
PMS 
CMV 
CMS 
Sl STPL 
PED 
PMD 
PMS 
CMV 
CMS 
S3 STPL 
PED 
PMD 
PMS 
CMV 
CMS 
STPL number of fruits per stalk P 
PED length of fruit stalk R 
PMD length of fruit S 
PMS width of fruit 
PZD characteristic fruit form 
CMV hieght of cupule 
CMS width of cupule 
CTD characteristics of scoles: trichom types 
COL characteristics of scoles: form of scoles 
s Sl S3 
[J93l !,8181 
i,ill2.I ~I 
1,0001 µKili 
1.0001 1..oo11 
IJ).Q.41 l.illllij 
l.0101 l.0041 
..QTI. 
,750 
lill 
,975 
,185 
,178 
Quercus pubescens 
Quercus robur 
Qercus pelraea 
1 stellulate trichomes on veins on upper leaf lamine side 
2 stellulate trichomes on veins and lamine slirface on upper leaf side 
3 stellulate trichomes on veins and lamine surface on lower leaf side 
S6 
,327 
,437 
.Jl.Q2 
,595 
,689 
,589 
,058 
,081 
,990 
.mJl. 
.Jm 
.,Q14. 
,213 
,094 
,246 
,084 
..Qlll 
..Qlll 
4 stellulate trichomes on veins on upper leaf sides and on whole surface of 
lower leaf side 
As expectated, the biggest differences were shown in the inter-species comparison of 
fruits of the studied three species of oaks. Only the fruits of pubescent oak and 
pedunculate oak showed significant differences in ali 6 morphological characteristics, 
the fruits of pubescent oak, pedunculate oak varicty RS and sessile oak typical 
samples varied in 5 characteristics (with the exception of the fruit cup height), as 
159 
Zbornik gozdarstva in lesarstva, 39 
well as the fruits of pure pedunculate oak and sessile oak variety Sl and the fruits of 
pedunculate oak and sessile oak varieties Rl and Sl. The fruits of pubescent oak 
differed from the fruits of all the other oak species in at least two rnorphological 
characteristics. 
In addition to those already mentioned, some significant differences also existed 
between the fruits of pedunculate oak and sessile oak; however, these differences 
were more frequent in the case of their varieties than in typical species samples. The 
most frequently occuring were differences in the fruit stalk length, fruit length and 
width and fruit cup width. 
Among ali these comparisons, the most interesting finding was that the statistical 
analysis had not shown any significant differences among individuals of pedunculate 
oak and the varieties of this species. Differences were found in 3 morphological 
characteristics at most, but it was not possiblc to find any rules to their occurance. 
In the case of sessile oak on the contrary, significant differenccs existed. With this 
species, the fruits of typical individuals varied significantly from the fruits of its most 
frequent varieties Sl and S3 in 5 rnorphological characteristics. On the other hand, 
among the fruits of sessile oak varieties, no such differences existed that a special 
rule could have been defined for their occurance. 
The other morphological characteristics of acorns were treated by special calculation 
procedures because the mean values calculation for these parameters gave no useful 
results. 
The first characteristic - typical form of a fruit - was in the phase of sample 
examination classified by the following standards: 
1 - smooth fruit 
2 - ring-striped fruit 
3 - longitudinally-striped fruit 
The mean value calculation for this parameter (see Table 11) only showed that two 
species of oaks had uniform fruit shape and that in the other specimens, the shape 
varied. The variation of this morphological characteristic can be seen in the following 
table. 
160 
Smole I., Batič F., The importance of morphological.. 
Table 13: Typical fruit shape distribution among the studied species of oaks 
Oak Typical fruit shape 
species 
Smooth Ring Longitudin. Tota! 
striped striped 
Quercus Number of samples 41 99 140 
robur % of samples 29,3 70,7 35,4 
% of total number of samples 26,2 50,3 
Quercus Number of samples 37 23 60 
robur l % of samples 61,7 38,3 15,2 
% of total number of samples 24,0 11,7 
Quercus Number of samples 3 2 5 
robur 3 % of samples 60,0 40,0 1,3 
% of total number of samples 1,9 1,0 
Quercus Number of samples 5 5 
robur 5 % of samples 100,0 1,3 
% of total number of samples 3,2 
Quercus Number of samples 4 6 10 
robur 6 % of samples 40,0 60,0 2,5 
% of total number of samplcs 2,6 3,0 
Quercus Number of samples 3 12 15 
petraea % of samples 20,0 80,0 3,8 
% of total number of samples 1,9 6,1 
Quercus Number of samples 44 14 17 75 
petraea 1 % of samples 58,7 18,7 22,7 19,0 
% of total number of samples 28,6 31,8 8,6 
Quercus Number of samples 6 12 12 30 
petraea 3 % of samples 20,0 40,0 40,0 7,6 
% of lota! number of samples 3,9 27,3 6,1 
Quercus Number of samples 5 5 
petraea 6 % of samples 100,0 1,3 
% of total number of samples 3,2 
Quercus Number of samples 6 18 26 50 
pubescens % of samples 12,0 36,0 52,0 12,7 
% of lota! number of samples 3,9 40,9 13,2 
Together Number of samples 154 44 197 395 
% of samples 39,0 11,l 49,9 100,0 
161 
Zbornik gozdarstva in lesarstva, 39 
It can be seen from the table that approximately one half of the fruits are longitudi-
nally-striped, there are 10% fewer smooth fruits is and the remaining fruits are ring-
striped. 
In the case of pedunculate oak - with the exception of variety RS - the combination 
of smooth and longitudinally-striped fruits is predominant, but the ratio of the two 
types shows no rules. 
With sessile oak, ali three types of fruits were found. With typical sessile oak trees, 
the combination is the same as in case of pedunculate oak, in varieties Sl and S3 all 
three fruit types were found, and the last variety S6 only had smooth fruits. 
Ali three types of fruits are also characteristic of pubesccnt oak, whereby ring-striped 
fruits are the most numerous. 
Special treatment was also required for two morphological features, terrned together 
the characteristics of the scales of the fruit cup: the type of hairs on the cupule 
scales and the shape of the scales. 
The type of trichoms on the cupule scales was classified in the analysis into the 
following two categories: 
1 - scale knobs covered with short, dense hairs, the scale tips hairless, 
2 - cupule throughout i::overed with short, dense hairs. 
From Table 11 it can be seen that this morphological characteristic is decisive for 
distinguishing the fruits of pubescent oak from the fruits of the other. two species 
(pedunculate oak and sessile oak), between which no significant differences of this 
kind exist. 
The second feature - the shape of the cupule scales - was classified into 4 categories 
with the following characteristics:3 
Triangular or ovate, rarely rounded, knobby at the bottom, with one or two 
processes, above with a triangular, clipped or rounded, overlapping, seldom 
protruding, flattened tip. Individual scales are evidently separate and are more 
or less evenly arrayed throughout the cupule (pedunculate oak, sessile oak). 
Ten:ding to triangular, tlattened, only at the bottom of the cupule considerably 
knobby, almost grown together, arrayed as wavy stripes or rings around the 
cupule. Above with triangular, more or less rounded, flattened tips, usually 
protruding from the cupule. The scales distinguishable and very evenly arrayed 
3 Descriptions of the cupule scales correspond to the actual findings of our examination of this 
morphological feature and are not entirely identical to statements in the literature (see Chapter 
3.1!). With pedunculate oak and sessile oak, two types of scalcs often appear, one of which (type 
.1) is not..even mentioned in the literature. Howe:,,er, this type of scale was the most frequent in 
our investigation. 
162 
Smole I., Batič F., The importance of morphological.. 
throughout the cupule (pedunculate oak). 
Lanceolate, wider and moderately convex at the bottom, above flattened, 
duek-beaked, at the top rounded or clipped, normally pressed to the cupule. 
They are very evenly arrayed (sessile oak). 
Lanceolate or almost lens-shaped, only slightly convex to almost fiat at the 
bottom, pressed to the cupule and very evenly arrayed (pubescent oak). 
Table 14: A review of the shape of cupule scales by thc studicd species of oaks 
Oak Shape Scales Fruit Cupule Together 
species 1 2 3 4 
Quercus Number of samples 90 50 140 
robur % of samples 64,3 35,7 35,4 
% of total number of samples 39,1 62,5 
Quercus Number of samples 30 30 60 
robur 1 % of samples 50,0 50,0 15,2 
% of tata! number of samples 13,0 37,5 
Quercus Number of samples 5 5 
robur 3 % of samples 100,0 1,3 
% of total number of samples 2,2 
Quercus Number of samples 5 5 
robur 5 % of samples 100,0 1,3 
% of total number of samples 2,2 
Quercus Number of samples JO 10 
robur 6 % of samples 100,0 2,5 
% of total number of samples 4,3 
Quercus Number of samples 15 15 
petraea % of samples 100,0 3,8 
% of total numher of samples 6,5 
Quercus Number of samples 50 25 75 
petraea 1 % of samples 66,7 33,3 19,0 
% of total number of samples 21,7 62,5 
Quercus Numbcr of samplcs 20 10 30 
petraea 3 % of samplcs 66,7 33,3 7,6 
% of total number of samples 8,7 25,0 
Quercus Number of samples 5 5 
petraea 6 % of samples 100,0 1,3 
% of total numher of samples 2,2 
Quercus Number of samples 5 45 50 
pubescens % of samples 10,0 90,0 12,7 
% of total number of samplcs 12,5 100,0 
Together Number of samples 230 80 40 45 395 
% of samples 58,2 20,3 10,1 11,4 100 
163 
Zbornik gozdarstva in lesarstva, 39 
Since the calculation of mean value for this characteristic only gives useful results for 
some groups of samples, additional cross tabular estimates were also made, similarly 
as for the shape of acorns. The results of these are presented in Table 14. 
From the table it can be seen that the first type of fruit scale is the most frequent; it 
is only absent in the fruits of pubescent oak. For the majority of pedunculate oak 
samples, the combination of the first two types of scale is characteristic and for the 
majority of sessile oak samples, a combination of the first and the third scale type. 
The latter combination also appears together with the fourth scale type, which is 
otherwise predominant in the fruits of pubescent oak. 
4 DISCUSSION 
The following findings of the investigation should be emphasized: 
Two levels or spectra of morphological characteristics have significance for the 
identification of oak species: visible and measurable characteristics and 
characteristics which can only be observed and evaluated (or measured) under 
a certain magnification. 
Visible morphological characteristics are mainly decisive in the identification 
of oak species, while hybrids or morphological varieties within species were 
identified on the basis of hairincss of parts of thc leaves. 
On the basis of the describcd criteria, thc rcsults of the primary phase of the 
investigation were verified and irrcgularities revealed were corrected. 
Afterwards, in a thorough analysis, new insights wcre achieved. 
The establishment that pedunculate oak and sessile oak had severa! 
morphological varieties was confirmed, while pubescent oak and turkey oak 
were shown to be morphologically uniform species, not affected by any 
external factors. No rule seemed to exist for the tcrritorial distribution of 
typical species and morphological varieties of pedunculate oak and sessile 
oak. For this reason it was not possible to define the areas of different 
intensity of mutual influence of the studied oak species. 
The hypothesis that the morphological characteristics of leaves from the sunny 
side of a tree crown vary significantly from the characteristics of leaves from 
the shady side (above ali the dimensions), was disproved by this investigation. 
Despite the unequivocal statistical results, this finding has to be judged with 
certain reservations, because of the way of collecting of leaf samples. As a 
rule, the leaves were collected at a height of approximately Srn. On the sunny 
side, the tree crowns are deeper and the sampling was not difficult; on the 
shady side, the lowest branches are sometimes more difficult to reach. In such 
a case, the leaf samples were taken from the shady parts of branches, but not 
strictly from the northern sidc of the crowns. Such a stylc of sampling could 
have had negative effects on the results of thc investigation. 
The statistical analysis showed that as far as the morphological characteristics 
of leaves were concerned, pedunculate oak only had two varieties. The first 
was identical to the pure species and the second to the hybrid Rl. The latter 
has shorter and narrower leaf lamina, not so many !obes and a longer petiole 
164 
Smole I., Batič F., The importance of morphological.. 
than trees of the pure species. Their fruits did not differ significantly. The 
deviations found suggest the possibility of the influence of pubeseent oak, 
although in a territorial sense, such a connection does not seem logicaL 
In the case of leaf samples of sessile oak, no significant morphological 
differences were found. The examination of fruits showed that the fruits of 
pure species differed significantly from the fruits of the most numerous 
hybrids S1 and S3. The latter were shorter and narrower, they had a shorter 
stalk and lower and narrower cupule than the fruits of the pure species. No 
significant differences existed in other characteristics of the fruits of the pure 
species and the two hybrids of sessile oak. On the basis of these differences, it 
was not possible to define exactly which oak species could have induced such 
changes. Besides due to the smaller number of samples - the results of fruit 
analysis are probably not so reliable as the results of the examination of the 
leaves. 
5 CONCLUSION 
By statistical analysis of a large number of leaf and fruit samples of four species of 
oaks, we wanted to find a possible relationship bctween the characteristic 
morphological fcatures of Ieaves and their typical hairincss (trichomes). On the basis 
of the examination of samples, an interna! classification of the species of pedunculate 
oak and sessile oak was performed. It turned out that in some cases, the relationship 
is very close, while in the others it is rather loosc or does not exist at ali. With 
pedunculate oak, a close relationship was found between the morphological 
characteristics of the leaves and the trichomes. No significant morphological 
differences existed among the fruits of this specics. It was not possible to define any 
such pattern for the leaves of sessile oak, but significant morphological variety 
existed among the fruits of this species. In both cases, the role of morphological 
features is characteristically narrowed to their dimensions, in which a certain rule 
could be observed. With very few exceptions, the range of dimension of 
morphological signs is greater among individuals of the pure species than among 
their hybrids. Nevertheless, it should be mentioned that we did not succed in finding 
any general rules about the relationship or interdependence of thc morphological 
characteristics of .oak leaves and specifical hairiness of their leaf parts. The finding 
is only valid for the pedunculate oak and sessile oak species, to which our full 
atterition was given during the investigation. 
An unwelcome methodological slip must be mcntioned, which could have affected 
the results of the invcstigation decisively. According to thc instructions of the 
Botanica.l Institute from Vienna, only oak leavcs samplcd in the summer months of 
July and August, and only from the trec crowns, should be used for cxamination of 
morphological characteristics of oaks. In the instructions it was additionaly empha-
sized that the leaves from adventive shoots and other secondary formations were not 
suitable for thjs purpose. The samples for our investigation were collected (in 
agreement with Austrian colleagues) in the first half of October, some of them also 
from adventive branches. 
165 
Zbornik gozdarstva in lesarstva, 39 
It can be concluded from everything mentioned above that it is not yet possible to 
speak about intraspecific morphological classification of pedunculate oak and sessile 
oak in Slovenia, since the present investigation has not given hard-and-fast enough 
evidence. 
In future investigations of oak taxonomy, the following topics will stili have to be 
worked on: 
Characteristics of the stipules 
Hairyness and other characteristics of the inflorescence 
The periods of leaf formation and flowering (phenological analyses) 
In executing ali three goals, the season of sampling or observation plays a decisive 
role. Some further tasks: 
Evaluation of hairyness of one year twigs and buds, distribution and shape of 
lenticeles 
Analysis of bark (the form of bark) 
Evaluation of distinguishing characteristics 
This investigation was only a first small step towards the study of oak in Slovenia. 
However, we hope that at least to a certain degree, our work with help elucidate 
some aspects of identification and intraspecific classification of Slovenc oak species -
which are, as elsewhere in Europe, already affccted by thc proccss of forcst decline. 
6 RESUME 
The results of oak sampling in Slovenia - which was carried out as a part of the 
Slovene-Austrian scientific cooperation programme are presented in Chapter 1. 
In Chapter 2, the methods of work are deseribed. Lcafed twigs and acorns from 160 
trees of pedunculate oak, sessile oak, pubescent oak and turkey oak were sampled at 
autochtonous oak sites throughout Slovenia. 800 leaf samples and 395 fruit samples 
were chosen for morphological observation. With Jeaf samples, the dimensions of 
leaf lamina and petiole were measured, the number of !obes to a leaf hlade was 
counted and the type and density of hairs (trichomes) on various leaf parts was 
evaluated under the stereo microscope. With fruit samples, the dimensions of fruits, 
cupules and fruit stalks were measured, the number of fruits to a stalk was counted, 
the fruit shape was recorded and the type of hairs and shape of scales on the cupule 
was evaluated. Ali the data were adaptcd for computcr analysis. 
In Chapter 3 and Chapter 4, the results of thc invcstigation and an explanation of the 
results ( discussion) are presented. As a first step, the primary results of sampling 
were supplemented and partly corrected. On the basis of thc hairiness of different 
leaf parts, an intraspecific classification into trces of the pure species and hybrids 
was performed for pedunculate oak and sessilc oak; pubescent oak and turkey oak 
once again proved to be pure species. The territorial distribution of "pure species" 
and hybrids has not shown any laws of the mutual influence of the studied species. 
166 
Smole I., Batič F., Thc importance of morphological.. 
The statistical analysis of leaf samples showed that no morphological differences 
between leaves from the sunny side and leavcs from the shady side of the trce crown 
existed among the studied four species. Pedunculatc oak • according to the 
morphology of leaf samples • was classified into two varictics. Thc first corrcsponded 
to thc pure species and the sccond to the most abundant pedunculate oak hybrid. 
The leaf samples of sessile oak were morphologically uniform. With fruits, the 
situation was the inverse; the acorns of pcdunculate oak were uniform, while the 
fruits of sessile oak were classified into three varietics, which corresponded to the 
pure species and its two most frequent hybrids. 
In the fifth, concluding chapter, it is mentioned that despite some positive results, it 
was not possible to define any general rule of relationship or interdependence 
between the morphological characteristics of leaf samples and thelr specifical 
hairiness pedunculate oak and sessile oak. The use of unsuitable samplcs could also 
have influenced the reliability of the .results of our investigation. The samples were 
collected in autumn instead in summer and some samples were taken from adventive 
shoots, which should not have becn done. The investigation has not, therefore, given 
reliable enough evidence for daiming an intraspecific classification of pedunculate 
oak and sessile oak undoubtedly exists in Slovenia. In future, many further questions 
will have to be answered and new explanations will have to be found to elucidate the 
problem of oak taxonomy in Slovenia. 
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slavia). Glas. šum. pokuse 24, Zagreb, p. 101 • 116. 
* Vegetacijska karta Brkinov z legendo (Vegetation chart of Brkini with a key). 
Ljubljana, Biološki inštitut Jovana Hadžija ZRC SAZU (manuscript chart M 
150 000, pages: Lendava 3, Čakovec 1 with a key). 
ZORN, M. 1967. Gozdne združbe in rastiščnogojitveni tipi v gospodarski enoti Tanča 
gora (Forest associations and site-growing types in the management unit of 
Tanča gora). Ljubljana, Biro za gozdarsko n~črtovanje. 
ZORN, M. 1958. Gozdne združbe in rastiščnogojitvcni tipi v gospodarski enoti 
Črnomelj (Forest associations and site-growing types in the management unit 
of Črnomelj). Ljubljana, Biro za gozdarsko načrtovanje. 
ZORN, M. 1975. Gozdnovegetacijska karta Slovenije. Opis gozdnih združb. (Forest 
vegetation chart of Slovenia. Description of forest associations.) Ljubljana, 
Biro za gozdarsko načrtovanje. 
168 
-°' \O 
Series 26 
OAK SUCCES. NO. NO. OF FRUIT FRUlT 
SPECIES tree sample FRUITS STALK DIMENSIONS 
TO A length length width 
STALK cm cm cm 
Quercus 26/1 1 3 3,0 2,7 1,6 
robur (6) 26/1 2 3 4,1 2,4 1,7 
26/1 3 1 2,6 1,2 1,2 
2611 4 3 4,9 2,9 1,6 
26/1 5 2 2,6 2,6 1,4 
Quercus 26/2 1 4 4,1 2,8 1,2 
robur (1) 26/2 2 3 3,7 1,4 1,1 
26/2 3 3 4,0 1,3 1,0 
26/2 4 4 4,3 1,6 1,0 
26/2 5 4 47 1,7 1,1 
Quercus 26/3 1 1 3,0 2,9 l,S 
robur 26/3 2 2 3,1 3,5 1,4 
2613 3 2 3,5 3,6 1,4 
26/3 4 l 2,7 3,5 1,4 
26/3 5 2 3 1 3,5 1,4 
Quen;us 26/4 l 1 5,8 1,7 1,1 
robur (1) 26/4 2 1 2,7 1,8 0,9 
2614 3 2 1,8 1,8 1,1 
26/4 4 3 2,9 2,0 1,2 
26/4 5 3 4,3 1.8 1,1 
Quercus 26/5 l 4 3,4 1,8 1,2 
robur (3) 26/5 2 2 3,2 2,1 1,4 
26/5 3 2 3,8 2,3 t,3 
26/5 4 1 1,1 2,1 1,2 
26/5 5 1 2,5 1,8 1,3 
FRUIT TYPE: 1 · smooth HAIRINESS 
2 • ring striped 
3 • longitudinally-striped 2 
Sampled on: 26.02. 1991, by Smole Ivan 
CUPULE 
Typical DIMENSIONS 
shape heigth width 
cm cm 
1 1,0 
1 1,1 
1 0,7 
3 0,9 
3 l,0 
l 0,7 
1 0,7 
1 0,7 
1 0,6 
l 0,7 
3 1,0 
3 0,7 
3 0,6 
3 0,9 
3 0,6 
3 0,4 
l 0,4 
l 0,4 
l 0,4 
1 0,4 
1 0,8 
1 0,6 
3 0,8 
1 0,7 
3 0,6 
on tbe scale 
knobs only 
througbout the 
fruit cup 
1,7 
1,7 
1,5 
1,6 
1,5 
1,3 
1,3 
1,3 
1,2 
1,3 
1,7 
1,5 
1,4 
1,6 
1,3 
1,1 
0,9 
1,2 
1,1 
1,1 
1,4 
1,6 
1,5 
1,2 
1,5 
Char. of scales 
hair shape of 
type scales 
1 1 
1 1 
1 1 
1 1 
1 1 
1 2 
1 2 
1 2 
1 2 
1 2 
1 2 
l 2 
1 2 
1 2 
l 2 
1 1 
1 l 
l 1 
1 l 
1 l 
1 1 
1 1 
1 1 
1 1 
1 1 
SHAPE OF 
SCALES: 
Quercus robur 
COMMENTS, 
EXPIANATIONS 
The prevatling type is I/II, with 
cleatly distinguishable scales, always 
convex at the bottom, flattened at 
the cupule edge. The tips 
overlapping 
The prevailing type is II; the scales 
are grown together, flattened, 
hardly distinguishable, arrayed ring-
like around the cupule. Only at the 
bottom, the scales are knobby 
Type II completely prevailing; the 
scales are grown together, fiat, 
arrayed ring-like and very 
homogeneous by apperance. The 
tips slightly protruding 
Specific type of fiat, slightly knobby 
scales witb distinct bairless tips, 
triangular and separate 
The type In is prevailing, however 
alrn the type 11 is admbred, 
especially at the top of fruit cup. 
Mostly the scales are clearly 
distinl!llishable. 
1 • single, knobby, ovelapping 
2 • grown together, fiat, protruding 
3 - lanceolate, knobby, overlapping 
4 • lanceolate, fiat, overlapping 
~ 
'G 
i ~-
!':' 
~ o 
-8 
;:r' 
2. o 
(!:. 
o 
!::. 
g. 
i,, ... 
Ul "' o s o o ::!. ii" "' e+ ;::;· -"' o ttl 
H-, "' o :t. 
"' O< ;,;' 
~'Tl t:t' 
E. ..., 
it ::, (O 
s· 
'O o ... 
s 
::i 
("') 
(1) 
g, 
3 
o ... 
'"O 
;:r' 
o o 
(l<l 
;::;· 
r:--
~ 
Successive number of a series: 26 
OAK SPECIES LEAF NUMBER OF 
DIMENSION LOBES 
Length Width Left Right 
cm cm side side 
Quercus 2611 O 11,3 8,0 5 6 
robur 26/1 O 9,8 7,7 6 6 
(6) 26/1 O 6,1 4,2 4 4 
26/1 O 15,1 10,1 7 7 
26/1 O 6,2 4,0 5 5 
Quercus 26/20 10,1 6,5 5 5 
robur 26/2 O 9,8 6,6 6 6 
(1) 2612 O 6,0 3,8 3 4 
26/2 O 10,5 6,2 5 5 
26/2 O 6,0 3,1 4 4 
Quercus 26130 9,9 5,1 6 6 
robur 26/3 O 7,9 3,5 6 6 
26/3 O 5,7 3,2 6 6 
26/3 O 10,5 5,0 7 7 
26/3 O 6,2 3,4 6 6 
Quercus 26140 10,8 6,7 7 7 
robur 26/4 O 9,1 5,4 6 7 
(1) 2614 O 6,6 3,2 4 3 
26/4 O 10,1 5,7 6 6 
26/4 O 5,7 ;;,o 4 4 
Q11ercus 26150 10,2 6,9 6 6 
robur 2615 O 8,2 5,0 6 5 
(3) 26/5 O 5,7 3,8 7 6 
26/5 O 11,9 7,8 6 7 
26/5 O 6,6 3,4 4 s 
HAIRINESS: e - simple 
z - stellate ( composed) 
g • bushy hairs 
Sampled on 11. l. 1991, by Smole Ivan 
PETIOLE 
length 
0,5 
0,3 
0,5 
0,8 
0,5 
0,4 
0,4 
0,4 
0,4 
0,4 
0,3 
0,4 
0,4 
0,6 
0,3 
0,8 
0,7 
0,4 
0,8 
o,s 
0,7 
0,7 
0,3 
0,8 
0,7 
Sampling site: SORŠKO POLJE, Godešič by Škofja Loka, along 
railway and the lineman's cabin 
LEAF HAIRINESS LEAF HAIRINESS - COMMENTS, EXPLANATIONS 
ABOVE BELLOW 
leaf veins margin leaf veins margin 
blade hlade 
e/1 - Stel!ate hairs on the veins and the 
e/1 entire upper surface a.nd on the veins 
e/1 below 
Z/1 e,Z/1 e,Z/1 the rest without comment 
Z/1 e/1 
e/1 e/1 Stellate hairs on the veins of the upper 
e,Z/1 e/1 e/1 surface 
e/1 e/1 e/1 - Simple transparent hairs on the veins 
e,Z/1 e/1 e/1 bellow 
e/1 e/1 e/1 
e/1 e/1 Except for the simple hairs on the venis 
e/1 above without comment 
e/1 
e/1 
e/1 
Z/1 e/1 Stellate hairs on the veins of the upper 
e/1 surface 
Z/1 e/1 • BeUow without comment 
e/1 e/1 
Z/1 e/1 
Z/1 e/1 e/1 - Stellate hairs on the leaf surface and 
z/1 e/1 veins upper surface 
z/1 z/1 e/1 e/1 Below without comment 
Z/1 e/1 e/1 
z/1 e/1 e/1 
DENSITY: single hairs O - samples from sunny 
side of tree crown 
O - samples from shady 
side of tree crown 
2 slight density 
3 medium density 
4 - great density 
~ ~ "5 
~ a 
~ ~ 
~ 
(Je. 
o 
~ 
N 
C. 
o 1:1) .... .... "' '"O 
::r' ~ o o s· 
~ o 
o en 
'"" 
1:1) 
o ;;i 
1:1) 1 @ 
5· ·<.,> 
'° en 
~ 
o 
::, ~· 
s· 
,-..,. 
'° '° ..... 
Smole I., Batič F., The importance of morphological.. 
Figure 2: Distribution of pure pedunculate oak (Q. robur L.) samples (open acorns), 
and it's hibrids (closed acorns) 
171 
Zbornik gozdarstva in lesarstva, 39 
> .g 
o :.::: 
:::s:::: o ro l/) 
~ <( 
o o:: g 
:C lL 
r- -,·rl' l/) ::::! 
l 1 >U lf)lf) r 
i\ i >U W 
;'{ ~ l/) 
~ :;i ~ 
-, c..) 
<( o::: 
:C lU 
<( :::::> zo -o <( Wz _Jo M ta <( ,.; 
o::: o:: .B 
a.. o ~ 
. 
1 ·.:; 
<C . .., ,::. 
Q .lil i!l ..., .i z 
~ UJ '8 ':, ':, 'O, ,, 
5! .!il ,. ,. .. [ .. o. . 
Figure 3: Distribution of pure sesile oak (Q. petraea (Mattuschka) Leih!) samples 
(open acorns), and it's hibrids (closed acorns) 
172