ANNALE S • Ser. hist. nat. • 10 • 2000 • 1 (19) 
original scientific paper UD C 581{497.4);632.5 
BIDENS PILOSA AN D CONYZA SUMATRENSIS, TW O NE W NATURALISED SPECIES IN THE FLORA O F SLOVENIA 
Livio POLDINI 
Department of Biology, University of Trieste, (-34127 Trieste, via I . Giorgieri 10 
Mitja KALICARiČ 
Science and Research Centre of the Republic of Slovenia Koper, 51-6000 Koper, Garibaldijeva 18 and Department of Siology, 
Pedagogical faculty, University of Maribor, Si-2000 Maribor, Koroška 160 
E-mail: mifja,ka!igaric@uni-mb.si 


ABSTRACT 
The species Conyza sumatrensis and Bidens pifosa are of American tropical and subtropical origin, but have in the last few years become well acclimatised in the Slovene coastal belt of Istra. This can be ascribed particularly to the milder sub-Mediterranean climate, which is clearly more advantageous to these species, and to the intensive sea traffic between the Northern Adriatic ports. Conyza sumatrensis can be found in dry, sunny and often stony habitats and is in the above mentioned area certainly not rare, while Bidens pilosa occurs only in a few localities on the Slovene side of the border, i.e. on more fertile and fresh ruderal sites. 
Key words: Conyza sumatrensis, Bidens pilosa, flora, distribution, Slovenia 
BIDENS PILOSA E CONYZA SUMATRENSIS, DU E NUOV E SPECIE NATURALIZAT E 
NELLA FLOR A DELLA SLOVENI A 

S IN TES! 
Bidens pilosa e Conyza sumatrensis sono specie di origine americana tropicale e subtropicale, ma negli ultimi anni si sono acc! i matate bene nella fascia costiera dell'lstria slovena. Questo falto pud es sere principalmente attribuito al clima submediterraneo mite, che favorises queste specie, nonché all'intenso traffico marittimo tra i porli de i Nord Adriático. Conyza sumatrensis puó es sere tróvala in habitat asciutti, soleggiati, spesso p tetros i e nell'area sopra menzionata e tutt'altro che rara. Bidens pilosa e in vece presente in pochi habitat dell'lstria slovena e cresce su terreni ruderali piu fertili e freschi e in vigneti. 
Parole d i save: Conyza sumatrensis, Bidens pilosa, flora, distribuzione, Siovenia 
INTRODUCTIO N tus, Artemisia annuua, A. verlotiorum, Bidens frondosa, Bilderdykia aubertii, Helianthus tuberosus, Tagetes Diversity of the adventitious flora of the Koper dis-minuta). The majority of these species are limited to the trict was described as early as in 1983 by T. Wraber, warmer, sub-Mediterranean part of Slovenia and some who listed quite a number of species of Central Ameri-merely to its coastal region. They have been brought can and Northern American distribution fAster squama-here with the aid of man and his communications, par­
77 
!.Mo POLDIN I & Milja K AU G ARI C: BIDENS PILOSA AN D CONYZA SUMATRENSIS, TW O NE W NATURAUSE D SPECIES (N THE Ft. O R A OF SLOVENIA, 77-80 
Fig. 1: Geographical distribution of Bidens pilosa in 
Slovenia. 
SI. 1: Geografska razširjenost Bidens pilosa v Sloveniji. 

ticularly Northern Adriatic ports of Koper, Trieste and Monfaicone. Most relevant for a further expansion of certain species to the warmer habitats on the Continent are of course railway connections. W e are in fact deal­ing with true corridors for the expansion of these species towards Ljubljana, Maribor and further on to Central Europe. Considering that the two found species, Conyza sumatrensis and Bidens pilosa, also originate from the warm (tropical and subtropical) parts of the Ne w World, they are distributed (for the time being) only in the coastal part of Slovenia, for they favour warm habitats without or with late frost. Characteristic of Bidens pilosa are its extremely late blossoming and fructification (September - November), while Conyza sumatrensis often develops winter rosettes. 
RESULTS AN D DISCUSSION 

Bidens pilosa L. 
This American tropical species has been expanding practically to all warmer parts of the world - Asia, Oceania, Africa and Europe, where it already occurs in England and France (Stace, 1997) as well as in Spain (De Bolos, 1998). In the neighbouring Italy it was re-Figs. 2, 3: Bidens pilosa with white marginal flowers in corded in Piemonte and Sicily (Pignatti, 1982), as well the head. In all other species these tubular-like flowers as in Liguria (Minuto, 1992), from where in fact origi-are yellow (Photo: M. Kaligarič). nates the (earlier collected) herbarium specimen in Lj U SI. 2, 3: Bidens pilosa bi po slovensko lahko imenovali (Marchetti, 5. 12. 1964). The localities from the coastal beli mrkač, saj so obrobni -cevasti -cvetovi v košku part of Slovene Istra are thus the easternmost in Europe. beli. Pri vseh drugih mrkačib so rumene barve (Foto: The main reason for the occurrence of this species here M. Kaligarič). is no doubt the busy sea traffic to and from the Port of 
Koper. Ankaran near the coast in the vicinity of the building of 
In Slovenia, the species was found for the first time the Slovene Navy (Kaligarič, LJU: October 15th 1989) in 1994 (Poldini, TSU: October 8t h 1994), i.e. at Valdol-(0448/2). its occurrence in this locality was again con­tra near Ankaran by the coast (0448/1), and later on at firmed in 1999, while its newly discovered localities 
78 ANNALE S - Ser. hist. nat. • 10 • 2000 • 1 (19) 
Uvio POI.DIN5 & Mitja KALIGARfČ: 8!DLN$ P1LOSA AN D CONYZA SUMA TREN51S, TW O NE W NATURAL!SED SPECIES IN THE ElOR A O F SLOVENIA, 77-80 
were: at a vineyard at Ankaran (Poidini, TSU, 1999} (0448/2), at Kortina near Rizana (Poidini, TSU: October 16th 1999) (0449/3), and at Sared above izoia (Kaligaric, LjU: November 1s t 1999) (0447/4) (Fig. 1). The species occurs on moderately damp and with nutrients rich ground, also as weed in vineyards, or ruderaiiy, so that flysch and alluvial deposits obviously suit its require­ments. The favourable conditions for the growth of this tropical-subtropical species are due also to the mild sub-Mediterranean climate in the coastal belt (Figs. 2, 3), From here probably the reason for this species inhabits only a narrow belt along the coast. Considering that very effective epizoocboria is characteristic of the genus Bid-ens, we can expect it to expand quickly towards south­east. it is difficult to predict, however, that its occur­rence as a weed plant will become a major problem, as is the case in the Ne w World and in some places of Asia and Oceania. In Slovene Istra, however, it is climatically on the very border of its occurrence. 

Conyza sumatrensis (Retz.) E. Walker 
Synonyms: Conyza albida Willd., C. naudini Bonet. 
The species has spread from the tropical America elsewhere, including Europe, particularly into the warmer parts of the Mediterranean, where it is already widely distributed in most of the Mediterranean coun­tries. Its first records in Italy were made as early as in 1964 by Anzalone (1964), i.e. in the area spreading from Piemonte to Sicily, The species reached the Slo­vene border in 1977, for this is the year since docu­mented with a herbarium specimen (Poidini, TSU) (Fig. 4). The more recent data regarding the Mediterranean also concern Albania (Baltisberger et al., 1987} and Croatia (Cami & jogan, 1998). This species has been for quite some time mistaken for the similar species Conyza bonariensis, which has been naturalised in the Mediter­ranean for a number of years. Austrian quotations of the species C. bonariensis have been rectified by Melzer (1998), who has now ascertained periodical occurrence of this species also out of the Mediterranean, i.e. in Austrian Styria. Ho w can w e distinguish between the two species? The most reliable marks are the marginal flowers in the inflorescence, which are in the species C. sumatrensis zygomorphic, while in the species C bon­ariensis all the flowers are actinomorphic. The species 
C. sumatrensis is otherwise much taller, with greater number of leaves, and branched out only in the upper part of the stem, while the leaves are bigger, wider and denticulate. C. sumatrensis is recognisable particularly by its often well-developed winter rosettes (see figure 5). These develop in extremely dry (strained) and warm habitats, such as cracks in asphalt, between pavements and roads, between pavements and houses, in the shel­ter of stone walls, etc. 
Fig. 4: Geographical distribution of Conyza sumatrensis in Slovenia. SI. 4: Geografska razširjenost Conyza sumatrensis v Sloveniji. 
Fig. 5: Conyza sumatrensis is recognisable even in mid­winter for its copiously developed rosettes; it can be found in distinctly dry and warm habitats, such as asphalt cracks (Photo: M. Kaligarič). Si. 5: Conyza sumatrensis je prepoznavna tudi sredi zime po obilno razvitih rozetah; najdemo jo v izrazito suhih in toplih habitatih, kot so razpoke v asfaltu (Foto: 
M. Kaligarič). 
The first reliable data for Slovenia are from 1984 (Poidini, TSU, December 21st 1984), i.e. from Gradno at Goriška Brda (9947/3). Poidini collected this species twice in 1997, namely in the centre of Izola (TSU, Oc­tober 18th 1997) (0447/4) and at Brestovica na Krasu (TSU, October 1st 1997) (0147/4). In the material from the Lj U herbarium there are two sheets from Lucija (T. Wraber, September 12th 1974) (0447/4) and Seča (T. Wraber, M. Lovka, October 2 n d 1981) (0547/2) that are identified as C. bonariensis. The bottom leaves are missing and the plants are more or less in the phase of fruits, but there are zygomorphic flowers also present in 
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tw o POLDIN! & Mk)a KALI CAR iC: BIDENS PILOSA AN D CONYZA SUMATRENSIS, TW O NE W NATURALISED SPECIES I N THE FLORA O F SLOVENIA. 77-80 
the flower head, which speaks of the fact that in both less restricted to the warm sub-Mediterranean climate of cases w e are dealing with C. sumatrensis and not C. Slovene Istra, where it inhabits explicitly dry and warm bonariensis. Apart from the stated herbarium specimens (usually anthropogenous) habitats, it can be therefore from Slovenia, the species C. sumatrensis was observed expected that it will not expand out of this area, al-practically in every Slovene coastal town: in Koper at its though this does not mean that some periodical finds are parking places and Skocjan inlet, in Izola also at its not excluded. Such case is the periodical occurrence of parking places, in Piran in its centre, etc. this species in Austrian Styria (Melzer, 1998). 
W e can conclude that this species, too, is more or 



BIDENS PtLOSA IN CONVZA SUMATRENSIS, DVE NOVI NATURAUZIRAN! VRSTI 
V FLORI SLOVENIJE 

Livio POLDIN! 
Oddelek za biologijo, Univerza v Trstu, !-34127 Trst, via L. Giorgieri 10 
Mitja KAUGARIČ 
Znanstveno raziskovalno središče Republike Slovenije v Kopru, Si-600Q Koper, Garibaldtjeva 18 in Oddelek za biologijo, Pedagoška fakulteta, Univerza v Mariboru, Si-2000 Maribor, Koroška 160, E-maii: mitja.kaligaric@uni-mb.si 
POVZETEK 
Vrst/ Bidens pilosa in Conyza sumatrensis sta ameriškega tropskega in subtropskega izvora in sta se v slovenskem obalnem pasu Istre v nekaj letih precej udomačili. Sem sta bili zanešeni ob pomoči človeka in njegovih komunikacij, predvsem severnojadranskih pristanišč: Kopra, Trsta in Tržiča. Bistvena okoliščina, ki je prispevala k njuni udomačitvi, pa je topla submediteranska klima, ki jo obravnavani tropsko-subtropski vrsti še lahko preneseta, saj jima ustrezajo topla rastišča brez ali s pozno zmrzaljo. Izjemoma oziroma prehodno se vrsta Conyza sumatrensis pojavlja tudi v ostrejših podnebnih razmerah. Tako so jo npr. našli že na avstrijskem Štajerskem. Sumatransko hudoletnico najdemo na suhih sončnih, večkrat kamnitih rastiščih in na omenjenem območju ni redka. Najdemo jo predvsem na suhih antropogenih rastiščih kot so nasipališča, parkirišča, gradbišča in v razpokah asfalta ali kamnitega tlaka. Od zelo podobne vrste Conyza bonariensis se loči po obrobnih cvetovi v koških, ki so pri vrsti C. sumatrensis tudi zigomorfni, pri vrsti C. bonariensis pa so vsi cvetovi aktinomorfni. Sicer pa je vrsta C. sumatrensis znatno višje rasti, bolj gosto olistana, razrasla le v zgornjem delu stebla, listi pa so večji, širši in imajo izrazitejše stranske žile. Posebej je vrsta C. sumatrensis prepoznavna po svojih pogosto lepo razvitih zimskih rozetah. Vrsta Bidens pilosa je redkejša in jo v Sloveniji najdemo v Ankaranu in Valdoltri, v Korttni nad Rižano ter v Šaredu nad Izolo. Zanjo sta značilna izredno pozno cvetenje in fruktifikacija (september - november), uspeva na nekoliko bolj rodovitnih in svežih ruderalnih rastiščih. V tropskih in subtropskih predelih Azije in Oceanije postaja vrsta Bidens pilosa zelo invazivna in nadležen plevel. Ker je v Sloveniji na klimatski meji uspevanja, takšnega problema z njo vsaj za zdaj še ne pričakujemo. Ker so jezičasti cvetovi v koških bele barve - običajno so v tem rodu rumeni ­predlagamo slovensko ime "beli mrkač". 
Ključne besede: Conyza sumatrensis, Bidens pilosa, flora, razširjenost, Slovenija 
REFERENCES 
Anzalone, B. (1964): U n nuovo Erigeron nella Flora Italiana. AnnaÜ di Botanica, 28(1), 25-39. Baltisberger, M. & W . Lippwerf (1987): Composíten aus Albanien. Candollea, 42, 679-691. Bolos de í Capdevilla, O. (1998): Atlas Corologic de la Flora Vascular deis Paísos Catalanas. Part I: Abies -Lagoecia. Institut d'Estudios Catalanas, p. 140 (Bidens pilosa), p. 270 (Conyza sumatrensis}, Barcelona. Carni, A. & N. Jogan (1998): Vegetation of thermophilic trampled habitats in the bay of Kvamer. Natura Croatica, 7(1), 45-58. 
Melzer, H. (1998): Neues zur Flora von Steiermark, 
XXXVII. Mitt, naturwiss. Ver. Steiermark. Band 128,1 -78. Minuto, L. (1992): Bidens pilosa L. (Compositae). In: Segnalazioni Floristiche italiane. Informatore Botanico italfano, 24(3), 216-217. Pignatti, S. (1982): Flora d'italia. Edagricole, Vol. III. p. 54 (Bidens pilosa), Bologna. Stace, C. (1997): Ne w Flora of the British isles. Cam­bridge University Press, p. 725 (Conyza sumatriens), p. 754 (Bidens pilosa), 2 ed., Cambridge. Wraber, T. (1982): Aster squamatus (Sprengel) Hieron tudi v Sloveniji (Prispevek k adventivni flori Koprskega). Biol, vestn., 30(2), 125-137. 
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