Nephrolepis

Smith, Alan R. & Kessler, Michael, 2018, Prodromus of a fern flora for Bolivia. XXXVII. Nephrolepidaceae, Phytotaxa 334 (2), pp. 135-140 : 136-137

Key to species of Nephrolepis in Bolivia

1 Indusia at pinna apices round-reniform or orbicular, with narrow to open sinuses; sporangia projecting equally from all sides of the indusia; blade tissue abaxially with sparse to dense fibrillose scales and/or catenate hairs ............................................................. 2

– Indusia at pinna apices semicircular, lunate, or reniform, with broad, open sinuses, or sinuses lacking; sporangia projecting from the open sides of the indusia, which face the pinna apices; blade tissue abaxially glabrous ........................................................... 4

2 Costae adaxially with dense, catenate hairs 0.1–0.3 mm long ....................................................................................... N. biserrata

– Costae adaxially with sparse, fibrillose scales ................................................................................................................................. 3

3 Blades 5–8.5 cm wide; pinnae with basiscopic bases rounded to auriculate; indusia pale brown with dark brown centers, 1.1–1.3 mm wide; rhizome scales obscurely bicolorous, mostly pale brown, with entire margins; scales on petioles, rachises, and pinnae pale brown .................................................................................................................................................... N. exaltata (cultivated)

– Blades (7) 8.5–11 cm wide; pinnae with basiscopic bases cuneate; indusia dark reddish brown, 0.8–1.1 mm wide; rhizome scales distinctly bicolorous (with lustrous, reddish brown centers and pale brown, long-ciliate margins); scales on petioles, rachises, and pinnae castaneous ............................................................................................................................................................ N. rivularis

4 Pinna bases of distal pinnae basiscopically cuneate, ± perpendicular to rachises; rhizome scales weakly bicolorous; rhizomes erect, underground stolons lacking tubers ................................................................................................................................ N. pectinata

– Pinna bases of distal pinnae basiscopically rounded to cordate; rhizome scales concolorous; rhizomes well or poorly developed, tubers present or absent on underground stolons .............................................................................................................................. 5

5 Petioles stramineous; rhizomes poorly developed, underground stolons often bearing scaly tubers; pinnae apically acuminate, tapering gradually from the bases; indusia 1.5–2 mm wide ........................................................................................... N. undulata

– Petioles light brown to brown; rhizomes well developed, often forming erect caudices, tubers present on underground stolons, or tubers absent; pinnae apically rounded to acute, usually parallel-sided or slightly tapering; indusia 1–1.5 mm wide .................... 6

6 Rhizome scales orange to tan, entire; petioles and rachises persistently fibrillose-scaly, dull light brown; rachis scales bicolorous (pale with dark points of attachment); tubers borne on underground stolons often present ..................... N. cordifolia (cultivated)

– Rhizome scales castaneous, lustrous, with long-ciliate margins; petioles brown, lustrous, with a few scales at the bases; rachises glabrous except at pinna bases; rachis scales concolorous; tubers absent ....................................................................... N. pendula