BRYACEAE 67 



to the outer. Growing on the ground, rocks and walls, rarely 

 on wood of any sort. This is a very large and difficult genus. 



The border often varies on the same leaf. Lower leaves of 

 Bryum are usually shorter and broader than the upper leaves 

 and always have a shorter costa. The inner comal leaves are 

 usually larger and narrower than the general run of leaves on 

 the plant. The border of a Bryum leaf is usually most distinct 

 near the base and least distinct near the apex. In using the 

 key, select leaves in the lower part of the upper third of the leafy 

 portion of the stem and look for border in the upper third of 

 the leaf. The margin of the leaves is frequently strongly re- 

 curved and gives the appearance of a margin whether a margin 

 be really present or not. To make sure, the margin must be 

 flattened out by manipulation with needles and pressure on 

 the cover-glass. It may even be necessary to use scissors. 



Some of the species vary in the characters used in the key, 

 hence these species have to be included under more than one 

 of the headings. 



Height as used in keys and descriptions applies to thegameto- 

 phyte only. The leaves in Bryum are markedly smaller than 

 in Mnium, and the leaf cells are much more elongated. The 

 capsules are usually more slender, longer necked and more 

 pendent. 



Pohlia (Webera of the L. & J. Manual) is so much like Bryum 

 that a word of warning may not be out of place here. The leaf 

 cells in Pohlia are much longer than in Bryum. B. capillar e is 

 frequently mistaken for Mnium because of its short leaf cells. 



Key 



1 — Leaves bordered 2 



Leaves not bordered, at least in the upper half 7 



2 — Costa plainly vanishing below apex. (See also B. capillare) . cyclophyllum 



Costa percurrent or excurrent in some of the leaves 3 



3 — Teeth of peristome with oblique or vertical lines connecting the 

 transverse articulations; inner peristome without cilia, some- 

 what adherent to the outer pendulum 



Teeth of peristome without unusual markings; all rare; cilia lacking 

 or rudimentary, not appendiculate; mouth of capsule oblique. 



uliginosum 

 Teeth of peristome without unusual markings; cilia 2-4, nearly as 

 long as the segments, usually appendiculate 4 



