Mosses and Lichens 



HYPNUM: Sub-genus BRACHYTHECIUM, Schimp. 



The plants of this sub-genus are generally large, prostrate 

 or creeping, forming loosely matted tufts ; the stems branch 

 irregularly, the branchlets somewhat regularly branching again, 

 and covered densely with leaves. 



The leaves are broadly oval and oblong-lance-shaped, usually 

 with folds lengthwise; the apex is acutely pointed, either broadly 

 or narrowly so ; the base is heart-shaped (cordate)] the vein is 

 single, continuous or vanishing half-way ; the cells are usually 

 smooth and much elongated, the alar enlarged. There are no 

 small leaf-like organs (paraphyllia). 



Spore -cases. 



Stem-leaf. 



Portion of the base of leaf to show 

 enlarged cells at the angle . 



Brachythecium Starkii. 



The spore-cases are oval or oblong, short, nodding, usually 

 arched with a convex-conical, obtuse, or short-pointed lid ; they 

 are borne on smooth or rough pedicels. 



The generic name Brachythecium is derived from two Greek 

 words, @pa%v<;, short, and #77/07, a case, relating to the short 

 spore-case. 



The peristome is double, the outer teeth being united at the 

 base, slender, lance-shaped, closely and regularly cross-barred, 

 with a distinct median line ; the inner teeth are lance-shaped 

 with 2 to 3 well-developed cilia all attached to a wide basal 

 membrane. 



There are one hundred and sixty-three species known at 

 present, about forty being found in North America. 



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