Nephrolepis radicans(Burm.f.) Kuhn

Hovenkamp PH & Miyamoto F, 2005, A conspectus of the native and naturalized species of Nephrolepis (Nephrolepidaceae) in the world, Blumea 50, pp. 279-322 : 308-309

17. Nephrolepis radicans(Burm.f.) Kuhn - Map 5; Plate 2a

Nephrolepis radicans (Burm.f.) Kuhn (1869) 285 ; Backer & Posth. (1939) 93; Copel. (1958) 185; Holttum (1968) 381; Tagawa & K. Iwats. (1985) 176. - Polypodium radicans Burm.f. (1768) 233, pl. 66, f. 3 . - Type: Pryon s.n. (n.v.), Java.

Nephrolepis clementis H. Christ (1908) 272 ; Copel. (1958) 185. - Type: Clemens 920 ( P), Philippines .

Lepidonevron volubile Fee (1852) 301 . - Nephrolepis volubilis ( Fee) J. Sm. (1841) 413 ; Kunze (1848a) 236; C. Presl (1851) 44. - Type: Cuming 37 ( BM, P), Philippines.

Aspidium obtusifolium Willd. (1810) 231 ; Blume (1828) 145. - Nephrodium obtusifolium (Willd.) C. Presl (1830) 32 . - Nephrolepis obtusifolia (Willd.) C. Presl (1836) 80 ; Brack. (1854) 210. - Type: Klein s.n. ( Willdenow herb. 18756 , B).

Habit, rhizome morphology. Plants terrestrial, forming tufts of 3-5 fronds. Runners tendril-like, proliferous or free, 1 mm thick, branching angle divaricate or straight. Scales on runners very sparse or sparse, appressed, spreading or (some) squarrose. Tubers absent. Fronds 94-102 by 7.5-10 cm, stipe 12-14 cm long. Lamina base strongly reduced, tapering over 20-35 cm, basal pinnae 0.5-1 cm long, 2.5-3 cm distant, middle pinnae straight or slightly falcate. Sterile pinnae 3.5-4 by 0.9-1 cm, herbaceous, thick, base slightly to strongly unequal, basiscopic base rounded, acroscopic base truncate, slightly auricled, margin in basal part crenate, apex rounded or obtuse. Fertile pinnae 4.5-6 by 0.7-0.8 cm, otherwise similar to sterile ones. Indument. Basal scales peltate, appressed, 2 by 0.7 mm, central part dark brown or blackish, shining, margin in basal part hyaline, ciliate, in acumen pale brown (often abruptly distinct from the dark central part), entire or denticulate; strongly elongated, lightly coloured marginal glands present around the scale. Rachis scales sparse or dense, without a distinctly protracted acumen, appressed (often somewhat bullate when dry), light brown. Scales on lamina sometimes present, very few, appressed, on lower surface. Hairs on lamina absent, on costa constantly present (also on lower surface, usually sparse). Sori submarginal, 20-23 pairs on fully fertile pinnae, round, not impressed. Indusium reniform, with open sinus, attached at sinus.

Distribution - India, Burma, Thailand, Vietnam, Malesia to Moluccas, New Guinea, New Caledonia.

Habitat & Ecology - At low elevations to 1000 m, terrestrial and scrambling over shrubs or trees, on waste ground, in belukar, often in swamps or on riverbanks.

Note - One of the most distinct and easily recognizable species of Nephrolepis , with a unique growth form. In N. radicans the runners are strongly differentiated and three distinct types can easily be distinguished on a single plant. Thick runners which, in contrast to normal runners, tend to grow upwards, form dense scrambling thickets, attached to supporting vegetation by tendril-like runners originating on the frond-bearing rhizomes. These frond-bearing rhizomes are short, densely scaly side branches, each apparently with a limited growth and with a limited number of fronds; typically only 3 or 4 well-developed ones present at the same time. In addition, they also bear long runners which bear roots wherever they come into contact with a suitable substrate. Apart from this distinct growth form, this species is easily recognizable by the obtuse or rounded pinnae and the scales on the rachis of the fronds that are somewhat bullate when dry.