grout] 



SOME COMMON MOSSES 



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lamellae). One genus of the family, (Catharinea) , has leaves which 

 become curled and crisped when dry, besides the calyptra is almost 

 bald, this genus we shall barely mention. 



The rest of our members of this family are divided into two 

 genera, one Pogonatum, with the capsules cylindric and the other, 

 Polytrichum, with the capsules prismatic, usually four angled and 

 often almost cubical. In April the young sporophytes, which will 

 later develop the capsules, appear as hairy- tipped lances as shown 

 in the photograph. In June and July the capsules will become full 

 grown and the different species can easily be recognized. 



We have four common species of Polytrichium, P. commune, 

 P. Ohioense, P. juniperinum, and P. proliferum. These are easily 



Fig. 3. Capsules of P. ohioense X2. 



separated into two groups by the leaf -margins. The two species 

 named first have the leaf margins nearly plane and strongly serrate. 

 The teeth at the edges of the leaves are easily seen with a lens if 

 the leaves are moist. When dry the edges of the leaves curl in and 

 the leaves all fold up against the stem to prevent too great drying 

 out of the plant's tissues. 



The two last mentioned have the margins of the leaves thin and 

 membranous and closely infolded like the hem of a garment or 

 sheet. 



P. commune, the Common Hair-cap, often called Bird Wheat or 

 Robin's Wheat, is found everywhere in open fields among the grass 

 and in open woods. The capsules arc nearly cubical and the 

 calyptra comes to or below the base of the capsule. P. Ohioense 

 is more frequently found in the woods, the capsules arc much 

 longer than broad and are not entirely covered by the caly])tra. 

 P. pilijerum is so called because the leaves bear at their apexes tiny 



