As a result of a revisionary study of the Orthotrichaceae in Mexico, Orthotrichum hortonae Vitt sp. nov., Macromitrium sharpii Crum ex Vitt sp. nov., Groutiella chimborazense subsp. reesei Vitt subsp. nov. and Florschuetziella steerei Vitt gen. et sp. nov. are described as new. Macromitrium punctatum (Hook. & Grev.) Brid. is the earliest name for, and taxonomically synonymous with, Macromitrium brachyrhynchum (Schwaegr.) Schimp. ex C.Miill. and Macromitrium pentastichum C.Miill., while M. contextum Hampe appears to be the correct name for the species that most recent authors have called M. punctatum. Macromitrium pringlei Card. is taxonomically synonymous with Macrocoma frigida (C.Miill.) Vitt, with the latter species new to Mexico. Leiomitrium standleyi (Bartr. in Grout) Grout is a taxonomic synonym of L. scaberrimum (Broth.) Wijk & Marg. and is placed in the genus Macrocoma as M. scaberrimum (Broth.) Vitt n. comb. Groutiella tumidula (Mitten) Vitt n. comb. is considered the correct name for those specimens of the Groutiella mucronifolia-apiculata complex with broad leaves and small mucronate apices; G. apiculata is the correct name for populations with narrower leaves and longer apiculate apices, with G. mucronifolia (Hook. & Grev.) Crum & Steere synonymous with the latter name. A numerical analysis is presented as evidence for the specific distinction of G. tumidula and G. apiculata. Groutiella undosa (Card.) Crum & Steere is a taxonomic synonym of G. chimborazense, whereas G. wagneriana (C.Miill.) Crum & Steere is a separate taxon not found in Mexico. In Mexico there are presently 8 genera and 43 species (45 taxa) of Orthotrichaceae. The largest of the genera are Macromitrium (10 species) and Orthotrichum (13 species). Many of the species of Macromitrium (and the later segregates Groutiella and Macrocoma) were described by Mitten (1869) and in his work he gave the first 1This research was supported by the National Research Council of Canada through grant A6390 to the author for which I am grateful. I wish to thank R. Ross (BM), L. E. Anderson (DUKE), R. Diill (Duisburg), G. Argent (E), J. Engel (F), D. Pfister (FH), C. Steinberg (FI), P. Geissler (G), T. Koponen (H), W. Reese (LAF), C. Delgadillo M. (MEXU), H. Crum (MICH), M. Crosby (MO), J. Mickel and W. C. Steere (NY), R. Pursell (PAC), S. Jovet-Ast (PC), A. J. Sharp and D. Smith (TENN) and R. Gradstein (u), for kindly arranging loans of type specimens and Mexican material and especially Claudio Delgadillo M. for his time and efforts while I was in Mexico. 2 Department of Botany, University of Alberta, Edmonton, Alberta, Canada T6G 2E9. 0007-2745/79/001-019$2.15/0 This content downloaded from 207.46.13.111 on Tue, 09 Aug 2016 05:50:15 UTC All use subject to http://about.jstor.org/terms 2 THE BRYOLOGIST [Volume 82 comprehensive treatment of the family in South America. Perhaps Mitten's concepts in Macromitrium are best represented in a booklet of unpublished drawings which is presently located in the library of the Missouri Botanical Garden (ex the private library of W. C. Steere). New species of the family were added to the Mexican flora during the late 1800's and early 1900's by Bescherelle (1872) and Cardot (1909, 1910, 1911a,b, 1913). Grout (1944) published a synopsis of the Macromitriae present in North America and later (1946) revised the family in the Flora North America. Bartram studied the family, particularly Macromitrium, and published several new taxa, (Bartram, 1928 and in Grout, 1944) as well as a revisionary treatment (1949) of the Guatemalan representatives. Many of these taxa are currently known from Mexico. An enumeration of all moss taxa found in Mexico was given by Crum (1951), and he included a listing of specimens examined and localities for the species. He listed 28 species in the family (excluding Rhachithecium) as occurring in the country. Florschiitz's (1964) publication on the mosses of Suriname treated several of the species of Schlotheimia, Macromitrium and Groutiella present in Mexico and included critical comments on the nomenclature and taxonomy of these. Since that time, species have been added to the Mexican flora or critically discussed by Robinson (1964), Vitt and Crum (1968), Crosby (1970) and others. Both Macromitrium with about 460 published names (recognized in Index Muscorum) of which 40% are New World and Orthotrichum with about 200 names with a large percentage being New World as well, are badly in need of revision. Most of the tropical and southern hemisphere species have not been critically examined by modern taxonomists. Thus, describing new taxa is hazardous, as numerous names are hidden in the literature. Realizing this, as well as having examined as much material as possible from the herbaria with major representation in the New World, the taxa described below have a good chance of not having been previously published. It is best to have usable names available now, rather than to wait until someone has monographed these genera and we have a better knowledge of the identities of all types. Orthotrichum hortonae Vitt sp. nov. FIG. 1-9, 62, 64 Plantae 0.5-3.0 cm altae, robustae, luteo-virides vel olivaceae. Folia ubi sicca patento-flexuosa, 2.0-4.0 mm longa, lanceolata, acuminata vel angust acuta, marginibus integris, ad basim revolutis, et apicim planis; cellulae superioris 7-12 ,m latae, papillatae; cellulae basilares elongato-rectangulatae. Flores gono-autoici. Setae (2.0)4.0-9.0 mm longae, + flexuosae; capsulae 1.52.5 mm longae, cylindricae vel ovato-cylindricae, exsertae, octo sulcatae; stomata basi capsularum superficialia; peristomium duplex; dentes exostomii 16, recurvi; segmenta endostomii, granulato-papillata. Sporae (25)27-33(38) jm latae. Calyptrae conico-oblongae, laeves, pilosae. Plants 0.5-3.0 cm high, robust, in loose, yellow-green to light-green, rarely olivegreen tufts. Stems one to several times branched, ascending, curved or erect, flexuose. Leaves loosely flexuose-spreading when dry, wide-spreading flexuose to spreadingrecurved when moist, 2.0-4.0 mm long, lanceolate, gradually acuminate to + narrowly acute, not keeled in upper portion; margins revolute in lower half to 2/, usually plane in upper 1/3 of leaf, entire; costa ending just below the apex; upper cells 7-12 tm wide, irregularly hexagonal to rounded, with 1-3 conical to forked papillae per cell; basal cells narrowly rectangular to elongate, usually nodose, grading to short-rectangular at the margins. Perichaetial leaves similar to vegetative leaves. Goniautoicous. Setae (2.0)4.0-9.0 mm long, usually flexuose; capsules 1.5-2.5 mm long, fully exserted, cylindric to ovate-cylindric when mature, cylindric when old, almost smooth to lightly 8-ribbed in upper half; exothecial cells not much differentiated; stomata superficial, conspicuous and numerous in lower half of capsule, often visible as whitish, raised This content downloaded from 207.46.13.111 on Tue, 09 Aug 2016 05:50:15 UTC All use subject to http://about.jstor.org/terms