Ornamental cultivars of the genus Polypodium L.

117 Ornamental-cultivars-of-the-genus-Polypodium-L. 117 Ornamental cultivars of the genus Polypodium L. EL BIETA ZENKTELER Department of General Botany, Institute of Experimental Biology, Adam Mickiewicz University, Umultowska 89, PL-61-614 Poznañ, e-mail: elzbieta.zenkteler@amu.edu.pl ABSTRACT: Ferns, which differ morphologically from other representatives of a given species, are selected, established in culture, and propagated as cultivars, i.e., cultivated varieties. Their originality raises their attractiveness for commercial purposes. The genus Polypodium has quite seldom been subjected to leaf shape modifications. The pinnatifid blades of the P. cambricum group are often classified as Cristatum (crested frond apex and pinnae), Cambricum (crested frond apex) and Pulcherimum (deeply dissected pinnae), while fronds of the four groups of P. vulgare are more different and include forms such as: Bifidum (basiscopic pinnules bifurcate), Cornubiense (bi- and tri-pinnatifid), Cristatum (pinnules multiply, forming the crest), and Ramosum (pinnules didymous at the top). ABSTRAKT: Okazy paproci, ró ni¹ce siê fenotypowo od pozosta³ych przedstawicieli danego gatunku, po wyselekcjonowaniu i wprowadzeniu do uprawy s¹ rozmna ane wegetatywnie jako kultywary. Ich oryginalny pokrój zwiêksza ich atrakcyjnoœæ handlow¹. W rodzaju Polypodium modyfikacje blaszki liœciowej wystêpuj¹ rzadko. Pojedynczo pierzasto-z³o ona blaszka przedstawicieli grupy P. cambricum najczêœciej klasyfikowana jest jako Cristatum (kiedy wyró nia siê kêdzierzawym wierzcho³kiem blaszki i listków I. rzêdu); Cambricum (o kêdzierzawym wierzcho³ku blaszki) oraz Pulcherimum (o g³êboko wcinanych listkach I. rzêdu). Liœcie nale ¹ce do reprezentantów czterech grup P. vulgare s¹ bardziej ró norodne morfologicznie. Wyodrêbniono tu formy takie jak: Bifidum (o listkach I. rzêdu rozwidlonych tylko u podstawy blaszki), Cornubiense (o listkach podwójnie i potrójnie siecznych), Cristatum (o kêdzierzawym wierzcho³ku blaszki i listków I. rzêdu oraz Ramosum (o listkach I. rzêdu rozwidlonych na szczycie). KEY WORDS: Polypodium, ornamental cultivars, pinnae partitioning patterns Species belonging to the genus Polypodium L. are widely distributed throughout Europe. Their fronds are characterized by a relatively small (20-35 cm, rarely about 50 cm) pinnatifid leaf blades. Primary pinnae (on average from 10 to 22 pairs) Zenkteler E. 2012. Ornamental cultivars of the genus Polypodium L. In: E. Szczêœniak, E. Gola (eds), Genus Polypodium L. in Poland. Polish Botanical Society, Wroc³aw, p. 117 121.

118 El bietaa-zenkteler 118 are alternately distributed on the rachis. The durability of the evergreen, leathery fronds is estimated for 2 3 vegetative seasons owing to their structure, which can resist drought and low temperatures. Frond shape, size and partitioning patterns of the primary or secondary pinnae are the basic criteria for classification of fern cultivars. In the genus Polypodium, structural modification of fronds is scarce and less attractive than in genera Dryopteris or Polystichum (Hosizaki, Moran 2001; Zenkteler 2009). The ornamental forms of Polypodium, selected from natural sites and transferred to nurseries and growers collections, appear to be very unstable, often changeable and infertile. Therefore, these forms are propagated only vegetatively, especially by rhizome fragmentation. Ornamental modification of frond shape occurs more frequently in two species of the genus Polypodium: a) Polypodium cambricum L. (syn. P. australe Fée), a mediterranean-atlantic diploid (2n=74) taxon, which in Poland is found only in gardens; and b) Polypodium vulgare, tetraploid (4n=148) taxon, common in the country and widely distributed in Europe. Modifications of a phenotype in representatives of P. cambricum are rare and according to Jones s classification (1987) belong to four groups: Cristatum with a prominently crested frond apex and pinnae (completely sterile plants); Cambricum with the crest and numerous glomerate, strongly dissected pinnae (completely sterile ferns); Pulcherimum with fronds relatively wide and deeply dissected pinnae (fertile plants); and finally Semilacerum with very narrow fronds, and only basiscopic pinnae dissected (Fig. 1A-B). P. cambricum as a diploid species is likely to deliver more modified forms than other polypody species. However, amateurs of the ornamental forms of P. cambricum do not possess the sufficient amount of propagated stocks. The only solution for them is to trade plants one for one. Cultivated species of the P. vulgare group (of an European origin) include e.g., P. interjectum and P. mantoniae, the latter described as a hybrid, difficult to identify. There are four groups of the ornamental forms of the P. vulgare complex, whose primary leaflets are of the very different shapes (Fig. 1C, 2A-C). These include the forms such as Bifidum (basiscopic pinnules bifurcate); Cornubiense (pinnules bi and tri pinnatifid); Cristatum (pinnules multiply, forming the crest at the frond apex), and Ramosum (pinnules didymous at the top and with shallowly serrate margins). Modifications of a frond shape in the common American taxon from the P. vulgare group, P. glycyrrhiza D. Eaton (syn. P. vulgare v. occidentale), whose rhizome contains large amounts of glucose, are similar to the Cambricum type. The taxon includes especially lush forms such as Grandiceps and Grandiceps Fox. Novelties of particular interest are Grandiceps Croker,

119 Ornamental-cultivars-of-the-genus-Polypodium-L. 119 Fig. 1A and B. Leaf blade modifications of the Cristatum type in Polypodium cambricum. Fig. 1C. Modification of the Grandiceps type in the Polypodium vulgare complex. (After Rickard 2000, modified). Fig. 1A i B. Modyfikacja blaszki liœciowej typu Cristatum u Polypodium cambricum. Fig. 1C. Modyfikacja liœci typu Grandiceps u przedstawiciela kompleksu Polypodium vulgare. (Wg Rickard 2000, zmienione). Diana and Bifidum, which grow vigorously and tolerate irregular watering. The group of less popular and usually difficult to establish forms of P. glycyrrhiza contains: Malahatense a fertile form of the Hornet type frond, with spines on all pinnae; Cornutum with a coiled apex of a rachis, and Accuminatum with very long and narrow fronds having acute primary leaflets. These attractive, very ornamental forms produce spores in the upper parts of their fronds. The above list of new wild findings in the genus Polypodium is still open

120 El bietaa-zenkteler 120 Fig. 2A. and B. Strongly dissected pinnulae of P. vulgare. Fig. 2C. Dentate margins of Polypodium cambricum pinnulae (After Rickard 2000, modified). Fig. 2A i B. G³êboko wcinane listki I. rzêdu u P. vulgare. Fig. 2C. Z¹bkowanie brzegów listków I. rzêdu u Polypodium cambricum (Wg Rickard 2000, zmienione). References JONES D.L. 1987. Encyclopaedia of ferns. Loth. Publ. Camp. London RICKARD M. 2000. The plantfinder s guide to garden ferns. David and Charles. pp. 130 142. RICKARD M. 2010. Recent development of Polypodium cultivars. Pteridologist 5 (3): 193 199. HOSHIZAKI B., R.C. MORAN 2001. Fern growers manual. Timber Press. Portland. ZENKTELER E. 2009. Ornamental ferns of the genus Dryopteris Adans. In: Szczêœniak E., Gola E. (eds.) Genus Dryopteris Adans. in Poland. Polish Botanical Society & Institute of Plant Biology, University of Wroc³aw, pp. 81 88.

121 Ornamental-cultivars-of-the-genus-Polypodium-L. 121 Ozdobne formy w rodzaju Polypodium Formy ozdobne w rodzaju Polypodium L. s¹ bardzo zmienne, czêsto niep³odne, dlatego podlegaj¹ wy³¹cznie wegetatywnemu rozmna aniu. Zalet¹ ich stosunkowo kruchych k³¹czy jest ³atwoœæ, z jak¹ poddaj¹ siê podzia³owi. W ozdobne modyfikacje blaszki liœciowej obfituj¹ dwa gatunki: Polypodium cambricum L. (syn. P. australe Fée) paprotka po³udniowa, gatunek diploidalny (2n=74), œródziemnomorsko-atlantycki, w Polsce w uprawie, rozwijaj¹cy liœcie póÿnym latem lub jesieni¹; oraz P. vulgare L. paprotka zwyczajna, gatunek tetraploidalny (4n=148), szeroko rozpowszechniony w naszym kraju. Kultywary P. cambricum nale ¹ do czterech grup: Cristatum ; Cambricum o brzegu listków pofa³dowanym i powcinanym; Pulcherimum o listkach I. rzêdu g³êboko wrêbnych, oraz Semilacerum, u której tylko dolne listki na osadce (3 4) s¹ g³êboko wcinane. Wœród form ozdobnych P. vulgare wydzielono cztery grupy ró ni¹ce siê kszta³tem listków I. rzêdu, a tak e pokrojem ca³ej blaszki liœciowej. S¹ to: Bifidum o dolnych listkach rozwidlonych; Cornubiense o listkach podwójnie potrójnie wrêbnych; Cristatum o listkach I. rzêdu zwielokrotnionych, tworz¹cych grzebieñ na szczycie osadki), oraz Ramosum o listkach wielokrotnie rozwidlonych.