狭翅铁角蕨 xia chi tie jiao jue

Asplenium alatulum Ching; A. centrochinense Christ; A. centrochinense var. major Bonaparte; A. centrochinense f. maximum C. Christensen; A. duplicatoserratum Ching ex S. H. Wu; A. fujianense Ching (1981); A. fujianense Ching ex S. H. Wu (1989); A. fujianensoides Viane & Reichstein; A. laui Ching; A. neomultijugum Ching ["neomutijugum"]; A. pseudowrightii Ching; A. serratissimum Ching ex S. H. Wu; A. subcrenatum Ching ex S. H. Wu; A. taiwanense Ching ex S. H. Wu; A. wrightii var. aristatoserrulatum Hayata; A. wrightii var. fauriei Christ; A. wrightioides Christ; Diplazium centrochinense (Christ) Tardieu.

Plants 35-70(-120) cm tall. Rhizome erect, short, scaly; scales brown, triangular to narrowly triangular, 5-7 × 1-1.2 mm, often costate with darker central zone and paler, denticulate glandular margin or long fibrillose. Fronds tufted; stipe dull to semi-shiny, grayish green to brown or stramineous-green, (12-)20-40(-50) cm, with scales similar to those on rhizome, subglabrous with age; lamina narrowly ovate-trullate to elliptic, (20-)40-70(-85) × (8-)15-25(-30) cm, base truncate, apex acute, 1-pinnate; pinnae 12-25 pairs, basal pinnae subopposite, others alternate, at an angle of ca. 50°-60° to rachis, with stalks (2-)4-8 mm, lower pinnae not much reduced, suprabasal pinnae narrowly ovate-trullate and often falcate, (5-)10-14(-23) × (0.8-)1.5-1.9(-2.5) cm, base asymmetrical, acroscopic side truncate at an angle of (40°-)55°-75°(-85°) to costa and often auriculate, basiscopic side cuneate, at an angle of (20°-)30°-40°(-60°), becoming decurrent on rachis in apical part of lamina, margin variable, from almost entire to crenate-sinuate, denticulate-serrulate or serrate to dentate, more coarsely dentate toward pinna apex, apex acuminate. Veins (1 or)2-forked, with terminal hydathode. Fronds papery, green to brownish green when dry, subglabrous; rachis dull grayish brown to green or purple, with reddish brown, reduced and fimbriate scales or 2 or 3 cellular uniseriate gland-tipped hairs, or subglabrous, terete abaxially, winged toward apex. Sori linear, (3-)9-12(-14) mm, on acroscopic veinlets, medial to supramedial; indusia grayish brown to dark brown, linear, membranous, free margin entire but often glandular and rolling back at maturity, opening toward costa, persistent.

On rocks by streamsides in forests, forested slopes; 200-1800 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Korea, Vietnam].

Most of the taxa put into synonymy of Asplenium wrightii were based on variable characters, often of relatively small plants (nicely fitting a herbarium sheet). Within this aggregate, the name A. wrightii is generally applicable to the larger plants, but existing herbarium material is inadequate as it does not cover the morphological variation and cytology is usually unknown. A set of morphological and size characters separates this complex into four major, but probably artificial, groups. A first, including A. wrightii, has pinnae more than 10 cm, sori more than 8 mm, and veins in the middle of the pinna 2-forked. A second group, including A. pseudowrightii, also has pinnae of more than 10 cm, but shorter sori (less than 8 mm), and veins only 1-forked in the middle of pinnae. Two groups with the largest pinnae less than 10 cm include A. wrightioides (with sori 6-11 mm) and A. centrochinense with sori less than 6 mm.

Japanese plants (Kurita, Rep. (Annual) Foreign Students’ Coll. Chiba Univ. 41-56. 1967; Mitui, Bull. Nippon Dental Coll., Gen. Educ. 4: 221-271. 1975) are octoploids (2n = 288), but Z. R. Wang (in K. H. Shing & K. U. Kramer, Proc. Int. Symp. Syst. Pterid. 133-134. 1989) reported tetraploids (2n = 144) from Yunnan. Our recent flow-cytometry showed additional ploidy levels (10x and 12x), but because no correlation was found between ploidy levels and gross morphological characters, we refrain from recognizing separate species pending further micromorphological, cytological, and molecular research.

Asplenium pseudowrightii was erroneously ascribed to Hainan. This was due to a wrong stamp on the holotype sheet in PE, which is without a collection label. However, all isotypes have the same collectors label (numbered "37818"), and collection labels state the plants origin: "Guangdong: Xin Yi, Har Sick Joun, stream side, 15 Nov. 1934." Some plants from near the type locality are tetraploid (the lowest ploidy level in this complex), while others are 12x (highest ploidy level in this aggregate).

The type of Asplenium duplicatoserratum ("S. S. Sin 469A") is also a syntype of A. centrochinense f. maximum. Asplenium duplicatoserratum is a large plant with serrate to biserrate pinnae similar to those of A. wrightii but with much shorter sori.

Asplenium ×wangii C. M. Kuo (Bot. Bull. Acad. Sin. 29: 109-111. 1988) is a hybrid between A. wrightii s.l. and A. bullatum; it was described from Taiwan and may be present where these taxa co-occur (Fujian, Guizhou, Hunan, Sichuan, Taiwan, and Yunnan). Asplenium ×shikokianum Makino (Bot. Mag. (Tokyo) 13: 13. 1899, pro sp., described from Japan), the natural hexaploid hybrid between octoploid A. wrightii and tetraploid A. ritoense, is not uncommon where its parents grow together (e.g., Guizhou, Taiwan). Asplenium ×kenzoi Kurata (J. Geobot. 11: 68. 1962) is from the cross with A. prolongatum.