七指蕨科 qi zhi jue ke
Zhang Xian-Chun; N. Sahashi
Ferns evergreen, medium-sized. Rhizomes shortly creeping, dorsiventral; primordia (buds) glabrous; fronds dimorphic; sterile blades (trophophylls) ternate with basal pinnae large; fertile blades (sporophylls) spikelike, with stalk attached at base of sterile blade; sporangia radially arranged in stalked clusters interspersed with small sterile projections. Spores trilete, globose, surface reticulate, with delicate projections ħ fused baculate.
Monotypic, widely distributed in tropics and subtropics of the Old World.
七指蕨属 qi zhi jue shu
Ophiala Desvaux.
Description and distribution as for the family.
七指蕨 qi zhi jue
Osmunda zeylanica Linnaeus, Sp. Pl. 2: 1063. 1753; Botrychium zeylanicum Swartz; Helminthostachys dulcis Kaulfuss; Ophiala zeylanica Desvaux.
Rhizomes 48 mm in diam., dorsiventral with fronds in two rows on dorsal side and fleshy, bearing thick roots on ventral side. Fronds usually single at rhizome apex, 2060 cm tall; stipe-base sheaths ca. 1 cm; common stipe fleshy, 1055 cm, 28 mm in diam., glabrous; sterile blade pinnate, ternate with basal pinnae large, lobed into 3 or 4 pinnules, thus appearing palmately dissected as a whole; pinnules elongate, 620 × 1.53 cm, base decurrent, margin irregularly toothed, apex acute or rounded; veins free, forked into parallel, close veinlets. Fertile blade spikelike, arising at top of common stipe; fertile blade stalk 410 cm, spikes 420 cm, 512 mm in diam.; fertile blade pinnae (sporangiophores) arranged in two rows on either margin of spike, branched 1 or 2 times, each consisting of stalk bearing a pseudowhorl of globular sporangia and 14 forked sterile apical appendages. 2n = 188.
Forests, edges of marshes; low elevations. Guangdong, Hainan, Taiwan, Yunnan [widespread: India, Japan, Philippines, Sri Lanka; tropical Australia, western Pacific islands].
Helminthostachys zeylanica is a rare, endangered species because of over-collecting for use in traditional medicine.