掌状叉蕨 zhang zhuang cha jue

Nephrodium subpedatum Harrington, J. Linn. Soc., Bot. 16: 30. 1877; Aspidium morsei (Baker) C. Christensen; A. subpedatum (Harrington) Diels; N. morsei Baker; Sagenia subpedata (Harrington) Nakai.

Plants terrestrial, 30-45 cm tall. Rhizome creeping to ascending, short, thick, 1-2 cm in diam., densely scaly at apex and stipe bases; scales brown, lanceolate, 4-5 mm, entire, apices long acuminate. Fronds clustered; stipe brown at base, stramineous upward, 20-30 cm, ca. 3 mm in diam., sparsely hairy. Lamina palmately 3-5-lobed, dark green when dried, deltoid-ovate, 15-20 × 12-16 cm, papery, abaxially densely hairy, adaxially glabrous, base cordate; costae and lateral veins stramineous, glabrous adaxially, densely hairy abaxially; terminal lobe elliptic-lanceolate, 15-18 × 5-7 cm, base slightly narrowed, apex long acuminate, entire or undulate to pinnatilobed; secondary pairs of lobes broadly lanceolate, 8-9 × 3-4 cm, bases not narrowed, apices long acuminate, undulate or subentire; basal lobes falcate-lanceolate, 5-6 × 2-3 cm, bases rounded-cuneate, apices long acuminate, entire. Veinlets forming subhexagonal areoles, raised on both surfaces, hairy, included veinlets forked. Sori rather large, close to lateral veins, locate at coupling veinlets of areoles, in 2 regular rows between adjacent lateral veins; indusia brown, clypeate, membranous, entire, slightly involute, persistent.

Forests on limestone. Guangxi, Taiwan [Myanmar, Vietnam].

Tectaria subpedata was treated as a synonym of T. polymorpha by Holttum (Fl. Males., Ser. 2, 2: 87. 1991). We have not seen the type from Taiwan, but we checked the specimens from Guangxi in IBSC. These specimens are obviously different from T. polymorpha in the size and location of sori, and the rhizome of T. polymorpha is never creeping, which is usually the case in T. subpedata.