Some Species of Brachythecium and Leskeoideae from Western North America

Abstract

Brachythecium sect. Velutinum, with five species and one variety in North America north of Mexico, is discussed. Brachythecium idahense Ren. & Card. is referred to the synonymy of B. velutinum. Brachythecium velutinum v. venustum (De Not.) Arc. (syn. B suberythorrhizon Ren. & Card. and B. petrophilum Williams) and B. fendleri, a valid species (syn. B. utahense James), are redescribed. Lescuraea iliamniana Lawt. is referred to the synonymy of L. julacea Besch. & Card. Leskeella nervosa v. sibirica (Arn.) Broth. (syn. Leskea catenulata v. acuminata Culm. and Pseudoleskeella catenulata v. filescens (Best) Lawt.) is discussed. The Velutinum section of Brachythecium as defined by Grout (1928) from North America consists of eight species and two varieties: B. bolanderi (Lesq.) Jaeg. B. erythorrhizon B.S.G. B. erythorrhizon v. suberythorrhizon (Ren. & Card.) Grout B. thedenii B.S.G. B. leibergii Grout B. collinum (C. Miill.) B.S.G. B. collinum v. idahense (Ren. & Card.) Grout B. utahense James B. petrophilum Williams B. velutinum (Hedw.) B.S.G. 1This research was supported by a great (NSF-G-19332) from the National Science Foundation to the University of Washington. I thank the directors of the herbaria of the following institutions for the loan of specimens: Museum of National History (Budapest), Botanical Museum (Helsinki), Royal Botanic Garden (Kew), Hattori Botanical Laboratory, New York Botanical Garden, and the Smithsonian Institution. 2 Department of Botany, University of Washington, Seattle 5, Washington. This content downloaded from 157.55.39.235 on Fri, 07 Oct 2016 05:57:15 UTC All use subject to http://about.jstor.org/terms 64 THE BRYOLOGIST [Volume 68 The section contains critical taxa which are frequently troublesome taxonomically. This paper represents an attempt to clarify them. Members of the group have been observed in the field for a number of years, specimens have been collected, and herbarium material1, including the available types, has been studied. As a result, five species and one variety in section Velutinum are recognized in North America north of Mexico. Members of Brachythecium sect. Velutinum are rather small plants, with leaves often falcate but not usually plicate, not decurrent or scarcely so, the margins typically serrate, and the seta rough or smooth. Brachythecium erythorrhizon does not belong here; the plants are larger than most members of section Velutinum, the leaves are plainly plicate, and the margins are entire except at the apex. European bryologists refer B. erythorrhizon to section Salebrosum with B. thedenii as a variety of it. No specimens of B. thedenii from America have been seen and it is doubtful that it occurs in the Pacific