Prodromus of a fern flora for Bolivia. X. Hymenophyllaceae 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 text Phytotaxa 2017 2017-11-21 328 3 201 226 http://dx.doi.org/10.11646/phytotaxa.328.3.1 journal article 10.11646/phytotaxa.328.3.1 1179-3163 Hymenophyllum subg. Mecodium C.Presl ex Copel., Philipp. J. Sci. 64: 93. 1937 . = Mecodium (C.Presl ex Copel.) Copel., Philipp. J. Sci. 67(1): 17. 1938 . Members of subg. Mecodium have entire segment margins and glabrous blades. Because of the limited number of characters and extreme morphological variation, species delimitation is particularly difficult in this group. Winged tissue along the petioles and rachises is often important for species identification, but may be lost or shrivelled during drying. Important diagnostic species characters include size of fronds; whether blades are planar or crisped; whether the petioles and rachises are green-winged or not; shape of the sori and involucres (more or less orbicular vs. broader than long, sometimes borne on a short, narrowly to broadly winged stalk); involucral bases rounded (vs. acute), tips entire (vs. lacerate).