云贵紫柄蕨 yun gui zi bing jue

Thelypteris yunkweiensis Ching, Bull. Fan Mem. Inst. Biol., Bot. 6: 274. 1936; Phegopteris yunkweiensis (Ching) Tagawa.

Plants to 1.5 m tall. Rhizome stout (short and ascending?, not seen). Stipe red-castaneous, shiny, 40-55 cm, base with dense brown, ovate-lanceolate, hairy scales, distally glabrous; lamina ovate, ca. 100 × 40-60 cm, not tapering to base, 2-pinnate-pinnatifid, apex acuminate and pinnatifid; pinnae 10 or more pairs, opposite, or distal ones subopposite and more oblique, sessile or proximal ones shortly stalked, proximal pair largest, 30-45 × 13-20 cm, oblong-lanceolate, bases symmetrical or basal several pinnules shortened acroscopically, pinnate-pinnatifid, acuminate at apices, basiscopic pinnules not elongate relative to more distal pinnules; pinnules 15-25 pairs per pinnae, 2.5-3 cm apart, alternate, spreading, mostly free from each other, sessile or narrowly adnate to costae, distalmost ones connected by a narrow wing, lanceolate, 6-13 × 1.4-2.4 cm, truncate at bases, pinnatifid 3/4-4/5 distance to costules, acute at apices; segments 15-20 pairs, falcate-lanceolate, margins crenate or entire distally, apices acute or obtuse; veins visible on both sides, especially adaxially, lateral veins forked, 4-7 pairs per segment. Laminae herbaceous, drying dark green, rachises and costae reddish, costules stramineous, abaxially with sparse acicular hairs or glabrescent along rachises, costae, and costules, with denser acicular hairs adaxially along costae and costules, glabrous on both surfaces on and between veins. Sori suborbicular or slightly oblong, borne at middle of lateral veins between costae and margins, 3-6 pairs per segment. Sporangia glabrous.

Forests beside streams. N Guizhou (Zunyi), SE Yunnan (Mengzi) [N Vietnam].