13. Nephrolepis lauterbachii H. Christ - Fig. 1k; Map 3; Plate 2e

Nephrolepis lauterbachii H. Christ (1901) 456. - Type: Lauterbach 578 (P? n.v.), New Guinea. Nephrolepis humatoides Alderw. (1924) 33. - Type: Lam 2047 (BO), New Guinea.

Habit, rhizome morphology. Plants forming tufts of 5 or 6 fronds. Runners often proliferous, 0.5-1 mm thick (or thinner), branching angle narrow. Scales on runners sparse, spreading. Tubers absent. Fronds 25-34 by 3-4 cm, stipe 3-8 cm long. Lamina base strongly reduced, tapering over 8-10 cm, reduced basal pinnae 0.9-1.1 cm distant, middle pinnae straight. Sterile pinnae 1.4-2 by 0.3-0.5 cm, leathery, base fully one-sided, basiscopic base narrowly cuneate, acroscopic base emarginate, cuneate or truncate, distinctly auricled, margin in basal part crenate, towards apex deeply dentate or incised, apex rounded or obtuse. Fertile pinnae 2 by 0.3-0.4 cm, more sinuose between the sori than the sterile pinnae. Indument. Basal scales peltate or type of attachment indistinct, spreading, 4 by 0.25 mm (or less), central part light brown, dull, margin not hyaline, in basal part irregularly lacerate, in acumen entire, without glands, apex acumen narrow, often sinuous, tapering to a long narrow apex. Rachis scales sparse (often caducous), with a well-developed protracted acumen, spreading, dark (distinctly darker than the basal scales), acumen entire. Scales on lamina absent. Hairs on lamina absent. Sori submarginal or medial, elongated. Indusium lunulate, attached at broad base.

Distribution - Restricted to New Guinea, Moluccas and the Solomon Islands.

Habitat & Ecology - At middle elevations, 900-2200 m, rarely at lower altitudes, from 250 m upwards, epiphytic or epilithic, in montane forest, often mossy or ridge forest.

Notes - Typical N. lauterbachii has small pinnae (<2 cm long), with a sinuous upper margin, at least the middle pinnae distinctly dimidiate, with the attachment at the basal corner. Often the upper pinnae are caducous, therefore plants often have long whip-like bare rachises in older fronds. Although runners are frequently collected, bulbils are very rarely present, and then very small. Many collections have young plantlets at more or less regular intervals on main runners that are slightly thicker than the other ones.

Nephrolepis lauterbachii can best be distinguished from N. cordifolia by the rachis scales, which are distinctly darker than the basal scales. In N. cordifolia, rachis scales and basal scales have the same pale to light brown colour. For the distinction from the South American N. pectinata, see under that species.