Eriosorus (Pabon-Mora & Gonzalez, 2016)

Kessler, Michael, Smith, Alan R. & Prado, Jefferson, 2017, Prodromus of a fern flora for Bolivia. XXVII. Pteridaceae, Phytotaxa 332 (3), pp. 201-250 : 219

Key to the Bolivian species of Eriosorus

1 Blades 4-pinnate or more dissected, scandent, twining, or scrambling, to 3 m long ....................................................................... 2

- Blades 1-to 3-pinnate-pinnatifid, erect or scrambling (scandent), to 1 m long ................................................................................ 3

2 Ultimate segments dichotomously lobed to deeply bifid, slender, each with 1 or 2 veins ............................................ E. flexuosus

- Ultimate segments ovate to cuneate, broad, each with 6–10 veins .......................................................................... E. orbignyanus

3 Blades 1–6 cm wide, linear to lanceolate, pinnae of roughly equal length throughout ................................................................... 4

- Blades 2.5–22 cm wide, deltate to rhomboid, the central or lower pinnae at least twice as long as the upper ones ....................... 7

4 Axes and blades glandular, lacking hairs ..................................................................................................................... E. ascendens

- Axes and hairs hairy ......................................................................................................................................................................... 5

5 Blades 2-pinnate to 2-pinnate-pinnatifid; pinnae ascending, set ca. 45°–70° to rachis ................................................. E. angustus

- Blades 1-pinnate to 1-pinnate-pinnatifid; pinnae perpendicular to rachises .................................................................................... 6

6 Blades 1-pinnate to 1-pinnate-pinnatisect; ultimate segments deeply bifid, each lobe with 1 or 2 veins; blade apices extended or somewhat curled .................................................................................................................................................... E. cheilanthoides

- Blades 1-pinnate-pinnatifid; ultimate segments irregularly divided, the lobes each with (1)3 or 4 veins; blade apices curled (as in Jamesonia ) ..................................................................................................................................................................... E. elongatus

7 Blades 3-to 3-pinnate-pinnatifid; pinnae stalked .............................................................................................................................. 8

- Blades 1-pinnate-pinnatifid to 2-pinnate-pinnatifid; pinnae subsessile ........................................................................................... 9

8 Rhizomes compact to short-creeping; pinnae abaxially hairy on veins and surfaces ......................................................... E. hirtus

- Rhizomes long-creeping; pinnae abaxially hairy on veins only ......................................................................... E. novogranatensis

9 Pinnae with dense, matted hairs on both surfaces, adaxially the hairs on the veins and surfaces ................................... E. stuebelii

- Pinnae sparsely hairy, adaxially the hairs restricted to the veins .................................................................................................... 10

10 Blades 2-pinnate-pinnatifid; hairs on petioles, rachises, and pinnae tortuous, not gland-tipped, the cells of the hairs laterally flattened .......................................................................................................................................................................... E. madidiensis

- Blades 2-pinnate; hairs on petioles, rachises, and pinnae rigid, gland-tipped (at least on the petioles), the cells of the hairs terete. ........................................................................................................................................................................................ E. rufescens