Niphidium

Smith, Alan R., Kessler, Michael, León, Blanca, Almeida, Thaís Elias, Jiménez-Pérez, Iván & Lehnert, Marcus, 2018, Prodromus of a fern flora for Bolivia. XL. Polypodiaceae, Phytotaxa 354 (1), pp. 448-450 : 448-450

Key to the Bolivian species of Niphidium

1 Rhizomes 3–5(6) mm in diameter; rachis scales persistent; primary lateral veins abaxially not or slightly raised, most of them darker than the blade surfaces .......................................................................................................................................................... 2

– Rhizomes (6) 8–15 mm in diameter; rachis scales absent or fugacious, rarely persistent; primary lateral veins abaxially raised, often lighter in color than the blade surfaces ............................................................................................................................................. 3

2 Rhizome scales usually appressed throughout, attached well above the bases, <3 mm long, with erose, often fimbriate margins; often epiphytic .............................................................................................................................................................. N. anocarpos

– Rhizome scales with tips usually spreading, attached near the bases,> 4 mm long, with erose or often ciliolate margins; often saxicolous .......................................................................................................................................................................... N. vittaria

3 Rhizome scales concolorous, castaneous; petioles usually winged to the bases ................................................ N. rufosquamatum

– Rhizome scales bicolorous; petioles not winged to the bases .......................................................................................................... 4

4 Rhizome scales not or scarcely clathrate, with small and occluded cell lumina, somewhat involute toward the apices, especially on those scales near the petiole bases; blades 2–5.5(7.5) cm wide ................................................................................... N. carinatum

– Rhizome scales clathrate, with translucent cell lumina, essentially plane throughout; blades (3) 5–12 cm wide ............................ 5

5 Cells in central portions of rhizome scales essentially isodiametric, or toward the apices slightly elongate, 1–2 times as long as broad; usually terrestrial or saxicolous, rarely epiphytic ............................................................................. N. albopunctatissimum

– Cells in central portions of rhizome scales elongate, usually 3–5 times as long as broad; usually epiphytic, rarely terrestrial or saxicolous ................................................................................................................................................................. N. crassifolium