MOSSES WITH A HAND-LENS 



37 



ASTOMUM. 



A. SuLLiVANTii Schimp. is associated in habitat with the 



two mosses mentioned above and is also small and cleistocarp- 



ous so that it is better to treat it here, although it belongs 



in the Tortula family. The plants are 



larger than in Pleuridium or Bruchia 



and are readily distinguished when dry by 



the spirally twisted leaves and also by 



the fact that the spores begin to mature 



in the fall. The plants without fruit much 



resemble Weissia viridula and the cuts of 



that moss will help in the study of the leafy 



part of this. The lower part of the stem 



is omitted in the cut and the capsules are 



Figure 12. Astroinum usually much more concealed by the leaves 



cnspum (From Dixon . ^ , , 



and Jameson.) when dry ; mdeed they are so hidden as to 



tingulshed from A '-'^ often overlooked, the plants are undoubt- 



Sullivantii with the gdly mistaken for sterile Weissia viridula. 

 hand-lens. 



DITRICHUM.* 



D. VAGINANS (SuUiv.) Hampe, the Dark Ditrichum, has a 

 habitat very similar to that of Ceratodon and at first sight might 

 be confused with it. The capsules are much the same color and 

 somewhat furrowed, but it is smaller with more erect symmetric 

 capsules that have much less conspicuous furrows when dry. 

 It matures its spores late in autumn, which of itself will be 

 sufficient readily to distinguish it from Ceratodon. It is not 

 frequent in the more northern portion of our range. 



D. TORTILE (Schrad.) Hampe, the Brown Ditrichum, is fre- 

 quent throughout in moist sandy or gravelly soil by roadsides 

 and in old fields. It is closely related to the preceding, but is 

 smaller, with light brown capsules which mature at about the 

 same time and are smooth when dry. 



It is more common than the Dark Ditrichum, especially 

 northwards. It grows in more moist places of the same general 

 nature, being especially fond of moist banks of recently disturbed 



*Ditrichum Timm..=Leptotrichu-m Hampe. 



