Prodromus of a fern flora for Bolivia. XXVII. Pteridaceae Author Kessler, Michael Systematic Botany, University of Zurich, Zollikerstrasse 107, CH- 8008 Zurich, Switzerland Author Smith, Alan R. University Herbarium, 1001 Valley Life Sciences Bldg. # 2465, University of California, Berkeley, CA 94720 - 2465 Author Prado, Jefferson Instituto de Botânica, Av. Miguel Estéfano, 3687, CEP 04301 - 902, São Paulo, SP, Brasil text Phytotaxa 2017 2017-12-22 332 3 201 250 http://dx.doi.org/10.11646/phytotaxa.332.3.1 journal article 10.11646/phytotaxa.332.3.1 1179-3163 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).