对生紫柄蕨 dui sheng zi bing jue

Polypodium rectangulare Zollinger, Syst. Verz. 37, 48. 1854; Dryopteris moussetii Rosenstock; Phegopteris moussetii (Rosenstock) Alderwerelt; P. oppositipinna Alderwerelt; Polypodium distans Kaulfuss var. minor C. B. Clarke; Pseudophegopteris oppositipinna (Alderwerelt) Ching; Thelypteris oppositipinna (Alderwerelt) Ching; T. rectangularis (Zollinger) B. K. Nayar & S. Kaur.

Plants 40-70 cm tall. Rhizome short, suberect. Fronds clustered; stipe red-castaneous, shiny throughout, 10-30 cm, with short spreading acicular hairs, base with narrowly lanceolate, brownish, sparsely hairy, thin scales; lamina narrowly oblong-lanceolate, 30-50 × 7-12 cm, slightly tapering and with pinnae more spaced proximally, pinnate-pinnatifid; pinnae ca. 20 pairs, opposite to subopposite, spreading, sessile and distal ones becoming narrowly adnate to rachis, proximal 1-3 pairs slightly shortened, to 3 cm, basal segments of proximal pinnae not significantly elongate or lobed, distal pinnae lanceolate, 4-7 × 0.8-1.8 cm, pinnately lobed to 3/4 of distance to costae, acuminate at apices; segments 12-20 pairs per pinna, obliquely spreading, oblong-triangular, entire along margins, obtuse at apices. Veins visible, lateral veins simple or occasionally forked, 3-5 pairs per segment, basal pair arising from above base of costules, acroscopic one of a pair running toward sinus but not reaching margin. Laminae herbaceous, drying greenish, adaxial surfaces nearly smooth except for hairs along costae, abaxial surfaces with sparse to many acicular hairs to 0.5 mm, hairs along costae denser, also sometimes with a few capitate short hairs between veins, rachises red-castaneous and with denser acicular hairs. Sori suborbicular, borne at middle or near tips of lateral veins, 2-4 pairs per segment. Sporangia each usually with 1 or 2 acicular hairs below annulus. 2n = 124.

Forests beside streams; 1000-1500 m. N Guangxi, SE Xizang, SE and W Yunnan [Bhutan, NE India, Indonesia, Malaysia, Nepal].

Dryopteris oppositipinnaAlderwerelt (Bull. Jard. Bot. Buitenzorg, sér. 2, 16: 24. 1914) is invalid (Melbourne Code, Art. 36.1(c)).