轴脉蕨 zhou mai jue

Aspidium sagenioides Mettenius, Abh. Senckenberg. Naturf. Ges. 2: 397. 1858; Ctenitis sagenioides (Mettenius) Copeland; Ctenitopsis obscura (Hooker) C. Christensen; C. sagenioides (Mettenius) Ching; C. sagenioides var. glabrescens Ching & Chu H. Wang; Dryopteris laokaiensis C. Christensen; D. sagenioides (Mettenius) Kuntze; D. sagenioides subsp. obscura (Hooker) C. Christensen; D. schizoloma (Alderwerelt) C. Christensen; Heterogonium sagenioides (Mettenius) Holttum; Lastrea melanopus (Hooker) Beddome; L. sagenioides (Mettenius) T. Moore; Nephrodium melanopus Hooker; N. obscurum Hooker; N. sagenioides (Mettenius) Baker; Phegopteris obscura (Hooker) Fée ex Christ; P. schizoloma Alderwerelt; Polypodium obscurum Hooker; P. viscosum C. H. Wright.

Plants terrestrial, 70-80 cm tall. Rhizome erect, short, ca. 1 cm in diam., densely scaly at apex; scales brown, broadly lanceolate, 4-5 mm, membranous, margins entire, apices acuminate. Fronds clustered; stipe deep castaneous to black, glossy, 30-40 cm, grooved above, occasionally clothed with lanceolate brown scales at base, with sparse light brown articulate hairs upward. Lamina bipinnatifid, dark brown when dried, elliptic, 40-50 × 20-25 cm, herbaceous, with sparse articulate brown hairs on both surfaces or abaxially glabrescent and adaxially with a few hairs, base retuse, margins ciliate, apex acuminate; rachises deep castaneous to black, glossy, ± clothed with articulate brown hairs; costae brown at base, stramineous upward, clothed with brown, articulate hairs; lateral pinnae 12-15 pairs, subopposite or alternate upward, interval 1.5-2 cm, applanate, subsessile; basal pinnae not shortened, reflexed, falcate-lanceolate, 10-12 × 4-4.5 cm, bases cuneate, apices acuminate, pinnatipartite nearly to costa; lobes 12-15 pairs, undulate or serrate, basal lobes shortened, middle lobes elongate toward base of lamina, ultimate ones acuminate; upper pinnae lanceolate, 10-12 × ca. 3 cm at base, pinnatipartite to 2/3, lobes ca. 15 pairs, subapplanate, interval 2-3 mm, ovate, 1.2-1.5 × 4-5 mm, obtuse, entire to undulate. Veins free, pinnate, 5 or 6 pairs, veinlets forked. Sori orbicular, terminal on veinlets, in 1 row between main veins and margin; indusia brown, orbicular-reniform. 2n = 80.

Wet dense forests; 100-300 m. Guangxi, Hainan, Yunnan [India, Indonesia, Malaysia, Myanmar, Thailand, Vietnam].

A more glabrous form of Tectaria sagenioides was found in Guangxi (Jinxiu) and Yunnan (Hekou), as Ctenitopsis sagenioides var. glabrescens, but this form does not merit taxonomic recognition. Holttum (Kalikasan 4: 205-231. 1975) stated that this species (the type of Ctenitopsis) belongs to the genus Heterogonium C. Presl, but no evidence is provided for this; and the species (and the related T. subsageniacea) fits morphologically well in Tectaria.