西藏轴脉蕨 xi zang zhou mai jue

Nephrodium ingens Atkinson ex C. B. Clarke, Trans. Linn. Soc. London, Bot. 1: 526. 1880; Aspidium cadieri Christ; Ctenitopsis cadieri (Christ) C. Christensen ex Tardieu & C. Christensen; C. ingens (Atkinson ex C. B. Clarke) Ching; C. matthewii (Ching) Ching; Dryopteris dissecta (G. Forster) Kuntze var. ingens (Atkinson ex C. B. Clarke) C. Christensen; D. ingens (Atkinson ex C. B. Clarke) Ching; Lastrea dissecta (G. Forster) Carruthers var. ingens (Atkinson ex C. B. Clarke) Beddome; Tectaria matthewii Ching.

Plants terrestrial, up to 3 m tall. Rhizome erect, short, stout, 1.5-2.5 cm in diam., densely scaly at apex; scales brown, (broadly lanceolate or) lanceolate, 6-9 mm, membranous, entire, apices acuminate. Fronds clustered, usually dimorphic, fertile fronds obviously narrowed; stipe dark stramineous to light brown, 30-80 cm, 5-9 mm in diam. at base, grooved above, with sparse (light) brown articulate hairs, lower part densely clothed with brown scales, similar to those of rhizome, few upward. Lamina tripinnate to quadripinnatifid, bipinnatifid upward, green or brownish when dried, triangular-ovate, 50-120 × 40-80 cm, thinly papery to membranous, both surfaces glabrescent, adaxially sometimes with a few brown articulate hairs, base cordate, apex (long acuminate or) acuminate; rachises, costae, and main veins dark stramineous to brown, densely clothed with brown articulate hairs; pinnae 10-15 pairs, lower part subopposite, oblique, interval 2-2.5 cm; basal pinnae largest, triangular, 22-42 × 15-30 cm, stalks 2-5 cm (with shorter stalks or subsessile upward), bases (rounded-cuneate or) cuneate and asymmetrical to nearly symmetrical, apices (long acuminate or) acuminate, basiscopic pinnules longer; middle pinnae elliptic-lanceolate, 20-35 × 8-20 cm, terminal pinna (rounded-cuneate or) cuneate at base, apex (long acuminate or) acuminate, largest basal basiscopic pinnules (broadly lanceolate or) lanceolate, 12-20 × 3.5-7 cm, bases obliquely cuneate, apices (long acuminate or) acuminate, bipinnate at base, bipinnatipartite to broad wings beside costa upward; ultimate pinnules 10-14 pairs, alternate, interval 1.5-4 mm, light upward, sessile and adnate to pinnule rachises, pair of basal pinnae larger, lanceolate, 2.5-4 × 1-1.5 cm, mucronate, basiscopic lobes decurrent at base, pinnatifid at base, scalloped or subentire upward; lobes 5-7 pairs, interval 1-1.5 mm, oblique, falcate-triangular, 3-4 × 3-4 mm, obtuse, entire, brown articulate ciliate on margin. Veins pinnate, free or anastomosing below indenture, veinlets 5-8 pairs, simple or forked, inconspicuous above, conspicuous and with sparse brown articulate hairs below. Sori orbicular, 4-8 pairs, terminal on veinlets, in center of midrib and margin; indusia orbicular-reniform, membranous, glabrous, entire, persistent.

Forests; 1000-2500 m. Guangdong (Lianxian), Xizang [NE India, Malaysia, Vietnam].

Tectaria matthewii only differs in its smaller size and does not seem to form a separate species. It is therefore (tentatively) united here with T. ingens. The isotype of T. matthewii in K is sterile.

Holttum (Fl. Males., Ser. 2, 2: 41. 1991) wrote that this species "is perhaps the nearest existing species to a prototype for the genus."