PLATYCERIACEAE [FIRST DRAFT]
鹿角蕨科 lu jiao jue shu
Zhang Xianchun (张宪春)[1];
1. PLATYCERIUM Desv., in Mem. Soc. Linn. Paris 6: 213. 1827.
鹿角蕨属 lu jiao jue shu
Epiphytic or occasionally epilithic ferns of very striking appearance, growing solitary or in clusters. Rhizome thick, short-creeping, concealed by roots and fronds; scales large, basifixed to peltate, mostly with a thickened dark central portion, margin ciliate, concolorous or pale brown; fronds clustered, extremely dimorphic; laminae fleshy, coriaceous, covered with stellate hairs when young; costa none, main veins conspicuous, dichotomously branched, usually several in each lobe or branch, minor veins visible or concealed, much anastomosing with free-included-veinlets. Base fronds persistent, forming a distinct basket, entire or forked several times; foliage fronds occur in pair, simple to variously dichotomously forked, erect to pendulous. Sori forming large soral patches, paraphyses numerous, stellate. Spores 64 per sporangium, or 8 (P. ridleyi Christ), monolete, smooth. Chromosome number n = 37.
15 species concentrate in SE Asia (8 species), Africa and Madagascar (6 species), only one isolated species in South America. One native in China, P. bifurcatum and P. alcicorna are often cultivated. The plants of this splendid tropical genus are much sorted for horticulture purpose; the wild population of P. wallichii in Yunnan is almost extinct. It is a national protected plant in China.
Together with Pyrrosia forming a natural monophletic clade in Polypodiaceae has long been recognised on morphological concordance. Recently molecualar phylogeny studies also support this relationship. The Platycerium-Pyrrosia clade in Polypodiaceae seems rather isloated from others by the characteristics of setllate hairs, and thick fleshy lamina.
1．Platycerium wallichii Hook., Gard. Chron. 764. 1858.
鹿角蕨 lu jiao jue
Rhizome thick, fleshy, short-creeping; scales basifixed to pelate, pale with dark brown central portion, stiff, about 10 x 0.4 mm, margin entire. Base fronds up to 40 cm or more, as wide as long, 3-5 times dichotomously lobed, lobes equal in length, obtuse ot acute, margin entire; main veins and secondary veins raised on both surfacea, smaller ones hardly visible, main veins dichotomous, secondary ones forming network, samller ones more copiously anastomosing; very thick and fleshy near base, more than 1 cm thick, thin and green at upper portion. Foliage fronds in pair, 25-70 cm long, subsessile, pendulous, lower portion divided into 3 uneven main lobes, the upper portion of the inner lobe repeatedly dichotomously branching, only the outer small lobe not fertile; main veins distinct, dichotomous, samller ones hardly visible, copiously anastomosing with included veinlets; thick, densely coved with stellate hairs; margin of lamina entire. Soral patches 2, large, at the base of the fisrt sinus of the two main lobes, mixed with stellate paraphyses. Spores 64 per sporangium, green color.
Epiphytic on tree trunks and branches up to very high from the ground, in tropical low land rain florest, alt. 210-950 m. W. Yunnan (Yingjiang, at the border with Myanmar) [E. India, Myanmar, Thailand and Malay].
[1] Herbarium, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, People’s Republic of China.