间断实蕨 jian duan shi jue

Acrostichum costatum (C. Presl) Wallich ex Hooker var. deltigerum Hooker, Sp. Fil. 5: 262. 1864; Poecilopteris costata (C. Presl) Beddome var. deltigera (Hooker) Beddome.

Rhizome 10-15 cm, up to 14 mm in diam., with 2 or 3 rows of fronds, covered with lanceolate (5-7 × ca. 1.5 mm), subclathrate, blackish scales. Sterile fronds pinnate, 40-115 cm; stipe 20-60 cm, 2-7 mm in diam. near base, with 7-14 vascular bundles; lamina purplish or purplish brown, 20-75 × 15-50 cm, widest at or below middle, herbaceous to leathery, terminal segment 14-40 cm, subarticulate or joined to rachis, bulbil subterminal; rachis not winged; pinnae 6-20 pairs, opposite or alternate, up to 6 cm apart, 10-30 × 2.5-6 cm, base ± symmetrical, usually narrowly, sometimes broadly attenuate or cuneate, margin usually ± entire or serrate-crenate, apex acuminate, lowermost 2 pinnae 1-10 mm stalked; veins forming a costal areole and several equally large distal areoles, veinlets 4 or 5 arising from each side of lateral veins anastomosing. Fertile fronds 40-120 cm; stipe 25-60 cm; pinnae 7-18 pairs, up to 6 cm apart, central pinnae 5-17 × 1.5-4.5 cm, lowermost 2 pinnae 1-9 mm stalked. Sporangia inserted on veins and near margin only, arrangement not acrostichoid.

Rain forests in valleys or on slopes; 300-700 m. Hainan, Yunnan [Bangladesh, Bhutan, India, Myanmar, Nepal, Thailand].

"Bolbitis virens (Wallich ex Hooker & Greville) Schott var. deltigera (Bedomme) Hennipman" is not validly published because Hennipman cited the Clarke name as the bsasionym (which itself is a new combination with a reference to Hooker).