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 Pteris websteri A.R.Sm. & J.Prado, Brittonia 56(1): 87(–88), fig. 2E–H. 2004. Range: — Colombia , Ecuador , and Bolivia (CO); to be expected in Peru as well. Ecology: —Rare (known from 2 collections); in secondary forests; 2100–2350 m . Notes: —For additional commentary, see Smith & Prado (2004) . Blades ternate, 2-pinnate-pinnatifid (3-pinnate-pinnatifid at base); proximal pinnae pedicellate, the pedicels very long (ca. 17 cm long), not winged; stipes lacking spines; venation free; awns present on costae adaxially. Pteridaceae subfam. Vittarioideae Link : Adiantum plus Vittarioid ferns = Adiantaceae Newman = Pteridaceae subfam. Adiantoideae R.M.Tryon = Vittariaceae Ching With the exception of Adiantum , this group contains almost exclusively epiphytes. It is characterized by glabrous, simple, apically forked ( Hecistopteris ), or variously 1–5-pinnate blades. Neotropical vittarioids were treated by Benedict (1907 , 1911 , 1914 ). Floristic accounts for vittarioids were provided by Tryon (1964) and Tryon & Stolze (1989) for Peru , and by Lellinger (1972) and Smith (1995) for the Guayana Highlands and Guayanan Venezuela . Blades of vittariads are generally fleshy (except Hecistopteris , where blades are relatively thin, chartaceous), with linear or reticulate sori along the veins. Most other epiphytic genera of ferns with simple, glabrous blades (except Loxogramme in Polypodiaceae , which has sori linear and oblique to the main midrib) differ by having parallel, open, free veins and acrostichoid sporangia ( Elaphoglossum ), or by having round sori and areoles with included free veins ( Campyloneurum , Microgramma ); x = 60. Martin et al . (2005) adduced evidence for CAM (Crassulacean acid metabolism) cycling-acid fluctuations, but without nighttime CO 2 uptake-in two vittariad species, Vittaria flexuosa (now Haplopteris flexuosa (Fée) E.H.Crane ) and Anetium citrifolium (now Polytaenium citrifolium ). The significance of this finding is both puzzling and needing further investigation. A largely pantropical subfamily with nearly 345 species in 12 genera, about two-thirds in Adiantum (PPG I 2016 ) . The genus is subcosmopolitan, but most species occur in the tropics and subtropics ; six genera of vittarioids occur in the Neotropics, three others in the Paleotropics, and Vittaria itself is amphioceanic (Neotropics and Africa). Phylogenetically, the vittarioid ferns are monophyletic and sister to Adiantum ( Rothfels & Schuettpelz 2014 , Pryer et al . 2016 ). On the surface, this seems like an unlikely relationship, both on the bases of general morphology and because the two lineages occupy dramatically different habitats-the vittarioids are mostly epiphytic on tree trunks and in forest canopies, while Adiantum is almost always terrestrial, or occasionally epipetic (rarely an epiphyte) in seasonal or evergreen forests ( Rothfels & Schuettpelz 2014 , Pryer et al . 2016 ). Both groups, however, have some species with idioblast cells in laminar tissue ( Sundue 2009 ).