Eriosorus angustus M.Kessler & A.R.Sm., Brittonia

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

Eriosorus angustus M.Kessler & A.R.Sm., Brittonia 59(2): 191, fig. 2C,D. 2007.

= Jamesonia angusta (M.Kessler & A.R.Sm.) Christenh., Phytotaxa 19: 20. 2011.

Range: — Endemic to Bolivia ( LP) ; known only from the type.

Ecology: —Rare; rocky trailside in secondary humid forests; 3200 m.

Notes: —Ultimate segments irregularly divided, the lobes with (1)3 or 4 veins each; blades basally abruptly reduced, the basal pinnae>50% as long as the longest ones. Differs from commoner E. cheilanthoides by its 2-pinnate-pinnatifid blades, abruptly reduced blades proximally (vs. blades with numerous gradually reduced pinnae), more ascending pinnae (set ca. 60° to rachis vs. 75°–90°), and slightly flexuous rachises. Differs from E. × flabellatus (the hybrid between E. cheilanthoides and E. flexuosus ) by the ultimate segments irregularly divided (vs. deeply bifid), the lobes with (1)3 or 4 (vs. 1 or 2) veins each, the blades basally abruptly (vs. gradually) reduced, and the basal pinnae>50% as long as the longest ones (vs. much shorter).