51. Asplenium rockii C. Christensen, Contr. U.S. Natl. Herb. 26: 332. 1931.
瑞丽铁角蕨 rui li tie jiao jue
Asplenium laciniatum D. Don var. crinigerum Beddome.
Plants up to 20 cm tall. Rhizome short, erect, or ascending; scales dark brown to black, narrowly triangular, entire or subfimbriate. Stipe stramineous, 2-4 cm, semiterete to terete, with spreading, narrowly triangular, dark brown scales, with long acuminate apex. Lamina narrowly elliptic to lanceolate, 12-18 × 2-3.5 cm, base reduced, 2-pinnate to 3-pinnatifid, apex acute; pinnae 15-20 pairs, subopposite to alternate, stalk ca. 1 mm, lower pinnae reduced, middle pinnae elliptic-subtriangular, 1.5-2.3 × 0.9-1.2 cm, base asymmetrical, acroscopic side truncate, basiscopic side cuneate, apex obtuse to subacute, 1-pinnate or pinnatisect; pinnules 3 pairs, anadromous, basal acroscopic pinnule largest, cuneate-spatulate, 6-8 × 3-4 mm, base cuneate and decurrent on costa wing, apex obtuse-truncate and serrate-lacerate, with 2-4 teeth up to 7 × 3.5 mm. Fronds subleathery, green, edges often revolute when dry, with narrow scales on veins, lamina subglabrous; rachis stramineous or green, sulcate adaxially, with dark brown, narrowly triangular, caudate scales. Costa minutely scaly abaxially, sulcate but with raised supravascular ridge, veins anadromous, not reaching margin. Sori 1 or 2(or 3) per pinnule, median on subtending veinlets, elliptic, 2-4 mm; indusia gray, elliptic, membranous, entire, opening toward costa or costule.
On rocks. Yunnan [Bhutan, NE and S India, N Myanmar, N Thailand].
Asplenium rockii is a distinct but rare species, which, according to flow cytometric analysis, is hexaploid in China.