Nephrolepis rivularis (Vahl) Mett. ex Krug, 1897

Hovenkamp PH & Miyamoto F, 2005, A conspectus of the native and naturalized species of Nephrolepis (Nephrolepidaceae) in the world, Blumea 50, pp. 279-322 : 309-310

18. Nephrolepis rivularis (Vahl) Mett. ex Krug - Map 6

Nephrolepis rivularis (Vahl) Mett. ex Krug (1897) 122 ; Proctor (1989) 263; Nauman (1992) 288; Mickel & A.R. Sm. (2004) 408. - Polypodium rivulare Vahl (1807) 51 . - Type: Ryan s.n. ( C), Montserrat.

Aspidium sesquipedale Willd. (1810) 230 . - Aspidium hoffmanseggi (Willd.) Poir. (1817) 509 (nom. illeg.). - Nephrodium hoffmanseggi Desv. (1827) (nom. illeg.). - Nephrolepis sesquipedalis (Willd.) C. Presl (1836) 79 . - Lepidonevron sesquipedale (Willd.) Fee (1869) 148 . - Type: Hoffmansegg s.n. ( Willdenow herb 19755 , B), Brasil.

Aspidium eminens Wikstr. (1826) 434 . - Type: Forsström s.n. (S-PA), Guadeloupe. Nephrolepis neglecta Kunze (1839a) 149 . - Type: Schiede s.n. ( LZ, destroyed, iso NY?), teste Mickel & A.R. Sm. (2004).

Nephrolepis valida Kunze (1848b) 229 . - Type: Kegel 1379 ( GOET n.v.), Surinam. Nephrolepis intermedia Sodiro (1893) 57 (nom. illeg. non Fée, 1857, see under N. undulata). - Type: Sodiro s.n. ( K, US), Ecuador.

Habit, rhizome morphology. Plants epiphytic, epilithic or terrestrial, forming tufts of 3 or 4 fronds. Runners 0.2-0.9 mm thick, branching angle narrow. Scales on runners sparse or dense, spreading or squarrose. Tubers absent. Fronds 39-165 by 5-13 cm, stipe 6-45 cm long. Lamina base reduced, tapering over 20-30 cm, basal pinnae 0.7-2.6 cm long, 2.5-3 cm distant, middle pinnae distinctly falcate. Sterile pinnae herbaceous, base strongly unequal, basiscopic base cuneate, acroscopic base truncate, distinctly auricled, margin in basal part entire or crenate, towards apex more deeply dentate, apex obtuse or acute. Fertile pinnae 2.8-6.7 by 0.5-1.1 cm, otherwise similar to sterile ones. Indument. Basal scales peltate, spreading or squarrose, 2-6.5 by 0.4-1 mm, central part rufous or dark brown, shining, hyaline margin narrow, usually very distinct even when narrow, or absent, margin in basal part irregularly lacerate or dentate, in acumen dentate or ciliate, marginal glands absent. Rachis scales dense or very dense, rufous or dark, with a well-developed protracted, spreading or squarrose, entire, very narrow, filiform acumen. Scales on lamina sometimes present. Hairs on lamina sometimes present, on costae absent. Sori submarginal or medial, 11-20 pairs on fully fertile pinnae, round, slightly impressed. Indusium reniform, with narrow sinus, attached at sinus.

Distribution - Throughout the Neotropics, from Cuba and Southern Mexico south to Bolivia, east to the Lesser Antilles and Brazil.

Habitat & Ecology - Commonly terrestrial or epiphytic, in forested, often moist habitats, at low to middle elevations, sea level to 2200 m.

Note - A distinct species, with submedial indusia that are firm, dark, and round with a very narrow sinus, sometimes appearing peltate (and occasionally reported as such). Rachis often with a peculiar, ʻscabrousʼ look, caused by the persistent scales, with spreading to squarrose appendages (not only the long filiform acumen, but also the appendages on the lacerate base are well-developed and erecto-patent).