| Description: |
Pelazoneuron As a result of recent studies by Fawcett & Smith (2021), as well as phylogenetic studies by Fawcett et al. (2021), the family Thelypteridaceae has received a new classification, which impacts the classification of species previously placed in Christella by Smith & Kessler (2017). Holttum (1974) described Christella sect. Pelazoneuron in his treatment of the Thelypteridaceae of Africa and considered most African species of Christella to belong to this section, in addition also to many neotropical species (unnamed by Holttum); he selected one of these, Christella patens, as the type of his section. Molecular data suggest that Pelazoneuron is rather distantly related to Christella (Smith & Cranfill 2002, Almeida et al. 2016, Patel et al. 2019, Fawcett & Smith 2021, Fawcett et al. 2021). Pelazoneuron, as newly defined, is an exclusively American genus of 16 species, four of which occur in Bolivia. Characters distinguishing Pelazoneuron from Christella and most other New World genera in the family include having the lowermost veins from adjacent segments connivent at an acute angle at the sinuses (vs. united at an obtuse angle below the sinus and with an excurrent vein to the sinus) and in having the proximal pinnae the longest, or nearly so. Pelazoneuron differs from many other cyclosoroid genera (in the Neotropics including Amblovenatum, Cyclosorus, Goniopteris, Meniscium, Stegnogramm a, and Steiropteris) in one or often more of the following characteristics: lack of protruding aerophores at pinna bases; relatively large, ± persistent indusia; lack of areolate venation and included veinlets; monomorphic fronds; lack of laminar buds; lack of sessile, resinous glands on veins and laminar tissue; generally long-creeping rhizomes; and somewhat weedy nature in semi-open habitats. All known species of Pelazoneuron, except of one species naturalized in Spain and East Africa, are restricted to the New World tropics and subtropics, from the southern U.S.A. through the Antilles, Mexico, Central ... |