掌状扇蕨 zhang zhuang shan jue

Neocheiropteris waltonii Ching, Hooker’s Icon. Pl. 32: t. 3158. 1932; Lepisorus sinuatus (Ching & S. K. Wu) S. L. Yu; Platygyria inaequibasis Ching & S. K. Wu; P. sinuata Ching & S. K. Wu; P. waltonii (Ching) Ching & S. K. Wu; Polypodium clathratum C. B. Clarke var. lobatum Takeda.

Plants up to 13 cm tall. Rhizomes creeping, 2-2.5 mm in diam., black, densely scaly; scales brown, ovate or ovate-lanceolate, clathrate, thin and fragile, margin with long spines; lumina transparent, isodiametric, oblong toward apex. Fronds remote or ± closely spaced; stipe straw-colored, 3-7 cm, angular, ca. 1 mm in diam.; lamina very variable, hastate to pedately 3-5-lobed, 4-7(-12) × 2-3 cm, middle lobe 3-6 × 0.5-0.8 cm, sometimes only some fronds enlarged at base, others 4-12 × 1-2 cm, membranous, abaxially sparsely scaly, scales ovate-lanceolate, lumina transparent, isodiametric, base broadly cuneate to subcordate, or auriculate, shortly decurrent, margin slightly undulate, apex obtuse; midrib raised abaxially, veinlets obscure. Sori close to costa, elliptic to suborbicular, ca. 2 mm in diam.; paraphyses ± black, almost ovate to subrhomboidal, lumina transparent, isodiametric. Sporangia platygyroid: spherical, indehiscent, annulus with broad, thin-walled cells. Spores ellipsoid, surface smooth.

Epilithic; 3400-5000 m. Sichuan, Xizang, Yunnan [N India, N Nepal].

Hemsley (J. Linn. Soc., Bot. 35: 206. 1902) treated material of this species as Polypodium hastatum Thunberg.

Platygyria inaequibasis was separated by Zhang et al (Acta Phytotax. Sin. 41: 401-415. 2003) on the basis of the less-developed lamina base, rather broader rhizome scales, and lanceolate paraphyses with more regular lumina. The considerable variation within Lepisorus waltonii is such that we have followed Yu and Lin (Acta Phytotax. Sin. 35: 343. 1997) who included that species within L. waltonii.