阴石蕨 yin shi jue

Adiantum repens Linnaeus f., Suppl. Pl. 446. 1782; Davallia chrysanthemifolia Hayata; D. cumingii Hooker; D. lepida C. Presl ex Goldmann; D. pedata Smith; D. repens (Linnaeus f.) Kuhn (1868), nom. cons., not (Bory) Desvaux (1827); D. subalpina Hayata; D. vestita Blume; Humata chrysanthemifolia (Hayata) C. Christensen; H. cumingii (Hooker) Brackenridge; H. kinabaluensis Copeland; H. lepida (C. Presl ex Goldmann) T. Moore; H. macrostegia Tagawa; H. pedata (Smith) J. Smith; H. trifoliata Cavanilles; H. vestita (Blume) T. Moore; Pachypleuria lepida (C. Presl ex Goldmann) C. Presl; P. macrostegia (Tagawa) M. Kato; P. pedata (Smith) C. Presl; P. repens (Linnaeus f.) M. Kato; P. trifoliata (Cavanilles) C. Presl.

Rhizome 0.5-3 mm in diam. (without scales), white waxy under scales. Scales brown or red-brown, with pale border from base to apex or not, narrowed evenly toward apex, not or seldom curling backward, peltate, 2.5-7 × 0.3-1.5 mm, with multiseptate hairs at least when young, or with marginal setae at least in distal part. Stipe adaxially grooved, 0.1-18 cm, glabrous or with few scales; lamina compound (pinnate with pinnatilobed to pinnatifid pinnae, or bipinnate to quadripinnate toward base and in middle part), simple (margin pectinate or pinnatifid), trifoliolate (pinnae ± divided), or pinnate toward base, ovate, deltoid and broadest toward base, 0.6-24 × 0.5-14 cm, glabrous, strongly dimorphic or not or slightly dimorphic. Longest petiolules 0-4 mm; pinnae linear-triangular, narrowly ovate, linear, or ovate to deltoid; longest pinnae 1-10 × 0.6-7 cm; pinnules (if present) of at least larger pinnae anadromous, linear-oblong or narrowly ovate; longest pinnules 5-55 × 5-20 mm; ultimate pinnae (if present) lobed almost to midrib or only shallowly lobed; ultimate segments or lobes obtuse or acute without a tooth. Dimorphic plants: lamina of fertile fronds pinnate with strongly dissected pinnae, bipinnate, or tripinnate toward base and in middle part; longest petiolules of fertile fronds 1-7 mm; pinnae deltoid, linear-triangular, or narrowly ovate, 1-8 × 0.3-2.5 cm; pinnules or pinna lobes deltoid or linear-oblong, 2-35 × 1.5-15 mm; ultimate pinnae linear-oblong; ultimate segments of fertile fronds 1-15 × 0.5-2 mm. Rachises and costae glabrous. Veins in sterile ultimate lobes simple, forked, or pinnate, reaching margin; false veins not present. Sori separate, borne several on a segment, or in much-divided fronds frequently single on a segment, at forking point of veins; indusium attached at broad base and hardly or not at sides, semicircular or ± triangular to rhomboid, wider than long, ± as wide as long, 0.3-1 × 0.3-1.3 mm, upper margin not elongated, truncate or slightly rounded, separated from or even with lamina margin; lamina generally extending into a tooth at both sides or only at outside of a sorus, or not extending into teeth beyond a sorus.

Low or high epiphytic, epilithic on various kinds of rocks, sometimes terrestrial, in very wet to dry sunny places; sea level to 3400 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [Cambodia, India, Indonesia, Japan, Malaysia, S Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; Africa, Australia, Indian Ocean islands, Pacific islands].

Humata repens is a very variable species. All the forms have in common the same spores, which vary in size because of polyploidy. The H. repens group, and probably the entire Humata clade in Tsutsumi, X. C. Zhang and Kato (Syst. Bot. 33: 44-48. 2008), is as far as we know polyploid and (?entirely) apomictic. Both H. trifoliata and H. vestita belong to this group. While H. trifoliata often is a young stage of H. repens (later in time more developed and more divided leaves may appear on the same rhizome), H. vestita is more recognizable when mature and is probably one of the sterile clones that so often occur within the H. repens group. In Peninsular Malaysia, H. vestita grows at higher elevations than other H. repens, but this has not been observed in China. It seems acceptable to distinguish H. vestita as merely a form of H. repens.