pleuropus. 395 



lanceolate, plicate, single-nerved, silky ; areolation linear, the 

 angular sub-quadrate. Dioicous. Seta rough or smooth. 

 Capsule erect, straight or very slightly curved. Inner peristome 

 imperfect, the processes short, slender, the cilia none or more or 

 less developed. Calyptra glabrous or hairy. 



This genus stands midway between the Orthothecium and 

 Camptothecium groups, having the erect capsule of the former 

 with the single nerve of the latter, to which it is without doubt 

 most closely allied. There are several continental species which 

 should be looked for here. 



The name Homalothecium is pre-occupied by Homalotheca, a 

 genus of Composite founded by Reichenbach in 1841. This 

 being the case it would appear that the correct name for the genus 

 is Pleuropus, founded by Griffith (Notulae ad plantas Asiaticas, 

 Pt. 2, p. 467) and published in 1849. Pleuropus was founded upon 

 three species, of which P. fenestratus Griff, may be considered 

 the type, and with which our European species are certainly 

 congeneric. 



1. Pleuropus sericeus Dixon (Hypnum sericeum L. ; 

 Homalothecium sericeum B. & S., plur. auct.) (Tab. LII. C). 



In wide patches, bright or yellowish green ; very glossy, pale 

 and silky when dry. Stems creeping, radiculose, with densely 

 crowded, erect, slender, often curved branches, somewhat terete 

 when dry. Stem-leaves rather large, about 1 line long, triangular- 

 lanceolate, gradually narrowed from the very base, at apex 

 ■filiform-acuminate , erecto-patent, when dry erect and somewhat 

 appressed ; at basal angles somewhat strongly denticulate, above 

 entire or obsoletely denticulate ; deeply 3-4 plicate ; one or other 

 margin usually very narrowly recurved ; nerve rather narrow,. 

 reaching f the length of the leaf. Areolation very long and 

 narrow, linear, slightly vermicular, 12-20 times as long as broad, 

 uniform to base ; at extreme base shorter and slightly laxer, not 

 much incrassate nor distinctly porose, at angles wider, quadrate- 

 hexagonal, irregular, forming distinct, somewhat enlarged,, 

 decurrent, toothed auricles. Branch-leaves smaller, narrower. 

 Seta rough. Capsule rather large, pale brown, oblong-cylindric, 

 often a little curved ; usually wider at base and somewhat 

 tapering to the narrowed mouth ; lid red, shortly rostrate.. 

 Calyptra often hairy at base. Dioicous. Male plants in separate 

 tufts, very slender. 



Hab. Trunks of trees and stone walls. Common. Fr. spring. 



