多形叉蕨 duo xing cha jue

Aspidium polymorphum Wallich ex Hooker, Sp. Fil. 4: 54. 1862; A. nantoense Hayata.

Plants terrestrial, 0.5-1 m tall. Rhizome erect, stout, 1.5-2 cm in diam., scaly at apex and stipe bases; scales dark brown and light glossy, pale at margins, linear-lanceolate, 6-7 mm, membranous, ciliate, apices long acuminate and curled. Fronds clustered, subdimorphic; fertile fronds rather tall, slightly narrowed; stipe stramineous, 20-60 cm, 4-5 mm in diam., grooved, glabrescent. Lamina simple or trifurcate to odd-pinnate, dark green or brown when dried, ovate to oblong, 30-60 × 25-30 cm, papery, abaxially pubescent, adaxially glabrous; rachises, costae, and lateral veins stramineous, glabrous adaxially, densely hairy abaxially, grooved adaxially and raised abaxially; terminal pinna simple or trifurcate, oblong, 18-20 cm, 7-9 cm wide at middle, entire or undulate, stalks 2-3 cm, bases slightly narrowed, rounded-cordulate, apices abruptly caudate; lateral pinnae 1-4 pairs, simple or basal pairs lobed, ovate-lanceolate, 18-20 × 6-8 cm, oblique, opposite, undulate to entire, interval 2-8 cm, bases gradually tapering, asymmetrical, cuneate, apices abruptly caudate; basal pinnae shortly stalked, sessile upward. Veinlets forming conspicuous subhexagonal areoles, raised on both sides, included veinlets forked. Sori orbicular, terminal on included veinlets or anastomosing veins, in 3-5 irregular rows between lateral veins; indusia brown, orbicular, membranous, entire, caducous.

On rocks or wet soil in forested valleys; below 100-1500 m. Guangxi, Guizhou, Hainan, Taiwan, Yunnan [Bhutan, Cambodia, India, Indonesia, Malaysia, Nepal, Philippines, Sri Lanka, Thailand, Vietnam].

Tectaria polymorpha is diverse in lamina shape, varying from simple or ternate to odd-pinnate. It is similar to T. herpetocaulos but can be readily distinguished from that species by its erect rhizomes.