Nephrolepis dicksonioides H. Christ

8. Nephrolepis dicksonioides H. Christ - Fig. 1b; Map 4

Nephrolepis dicksonioides H. Christ (1895) 241; Holttum (1968) 376. - Dicksonia nephrolepioides H. Christ (1895) 241. - Type: Sarasin 1030 (P n.v.), Celebes. [The type (Sarasin 1030) could not be located; however, its origin in Celebes puts it beyond doubt that it is this species and not N. abrupta with which it has been confused.]

Nephrolepis rosenstockii Brause (1913) 25. - Type: Schlechter 16494 (K, L, P), New Guinea.

Habit, rhizome morphology. Plants forming tufts of 2 or 3 fronds. Runners 1.5-2 mm thick, branching angle divaricate. Scales on runners dense, spreading. Tubers absent. Fronds 200 cm long (or more), 16-18 cm wide, stipe 33-35 cm long. Lamina base strongly reduced, tapering over 30 cm, basal pinnae 1.2-2.5 cm long, 4-6 cm distant, middle pinnae slightly to distinctly falcate. Sterile pinnae 9.5-11 by 1.6-2 cm, leathery, base strongly unequal, basiscopic base rounded or cordate, acroscopic base cuneate or truncate, not auricled, margin in basal part entire, towards apex crenate or serrate, apex acuminate or to 1.5-2.5 cm caudate. Fertile pinnae 10-15 by 0.6-1.2 cm, different from sterile pinnae in the margin deeply incised between the sori, especially towards pinna-apex, and the apex more gradually narrowed to a 2.5-4 cm long cauda. Indument. Basal scales pseudopeltate, spreading, 5 by 2-2.5 mm, central part rufous, shining, marginal glands absent, margin not hyaline, in basal part ciliate or fmbriate, in acumen ciliate or fmbriate. Rachis scales dense, with a well-developed protracted acumen, appressed (inconspicuous), hyaline or light brown, acumen ciliate. Scales on lamina absent. Hairs on lamina and costa absent. Sori marginal (or nearly marginal), often on dilated teeth, especially towards the pinna-apex, 20-32 pairs on fully fertile pinnae, elongated (sometimes confluent near the base of the pinna), not impressed. Indusium broad, attached at broad base.

Distribution - Eastern part of Malesia: Celebes, Moluccas, New Guinea, Solomon Islands.

Habitat & Ecology - Terrestrial, on rocks, or epiphytic. Disturbed places in lower montane forest, in ridge forest or disturbed secondary forest, 400 -1900 m.

Note - Nephrolepis dicksonioides has been confused with N. abrupta and N. acuminata. It has fertile pinnae similarly incised as typical specimens of N. acuminata, and marginal sori similar to those of N. abrupta, but differs from both in the indusium having a broad base, innervated by 2 or 3 veins. The apex of the sorus-bearing tooth is often dilated. From N. abrupta it can also be distinguished by the shape of the pinnae: the fertile ones are more constantly deeply divided, the sterile ones more distinctly acuminate, narrowing to a distinct cauda from c. halfway.