书带蕨 shu dai jue

Vittaria flexuosa Fée, Mém. Foug. 3: 16. 1852; Haplopteris modesta (Handel-Mazzetti) E. H. Crane; V. caricina Christ; V. costularis Ching; V. filipes Christ; V. japonica Miquel; V. lanceola Christ; V. modesta Handel-Mazzetti; V. nana Ching; V. ophiopogonoides Ching.

Rhizome shortly creeping; scales deciduous, yellow-brown, bright, iridescent, subulate-lanceolate, (2-)5-6 mm, 0.2-0.5 mm wide at base, margin denticulate, apex bristlelike, areole wall thick, dark colored. Fronds clustered; stipe slender, short, base pale brown, with small fibrous scales; lamina herbaceous, linear, 15-40+ × 0.4-0.6 cm, small ones 6-12 × 0.1-0.25 cm, narrowed gradually to both ends, base long attenuate; costa narrowly concave adaxially, raised abaxially, slender, veins invisible, margin revolute and partly covering sori. Soral line submarginal, immersed in groove, with a broad area between costa, but in narrow-fronded plants line occupying whole area when mature, fertile medially; paraphyses many, long, with head obconic, ± as long as wide. Spores monolete, oblong in outline, surface obscurely papillate.

Epiphytic or epilithic; 100-3200 m. Anhui, Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, Cambodia, India (Sikkim), Japan, Korea, Laos, Myanmar, Nepal, Thailand, Vietnam].

The narrow-fronded form, with soral line occupying area between costa, growing in crevices of rocks in dry conditions or on wet cliffs of caves, is also known as Vittaria caricina, V. nana, and V. modesta; the epiphytic long-fronded form from humid evergreen monsoon forests in E Himalaya is called V. ophiopogonoides; while intermediate forms are known as V. filipes or V. costularis. This species, widespread in E Asia, is very variable in size but constant in its scale and paraphysis characters and its lamina margin always revolute and partly covering sori.