i68 HOW TO KNOW THE MOSSES 



so long as in P. gracile; and the calyptra only partly 

 covers the capsule. 



Range, Newfoundland to Alaska, south to Alabama, 

 Missouri, and Oregon; Europe. 



Polytrichum ohioense, when not in fruit, cannot be 

 distinguished from P. commune and P. gracile, as the 

 leaves are similar, but it may be expected in moist, 

 shady places, usually in woods, while P. commune^ 

 although occurring in woods, is the common species in 

 more open places and grows more extensively, and P. 

 gracile is a rare species of elevated regions. See also 

 P . juniperinum, p . 165. 



Polytrichum commune L. typically has stems 6-10 

 inches loftg, with leaves very long, often % inch, rather 

 separated, wide-spreading when moist, folded when dry, 

 hut having the tips recurved and the shining leaf-bases 

 conspicuous. The plants grow in moist, shaded places 

 and are a rather bright green. The plants commonly 

 found in drier, more exposed places are probably P. 

 comjnune var. perigoniale (Michx.) Bryol. Eur. (Plate 

 VII, Fig. i). The stems of this variety are shorter, 

 usually 2-4 inches long, the leaves are a little smaller 

 and more crowded, so that when dry and folded tite leaf- 

 bases do not generally show, and the leaves are often a 

 darker green or olive, with only the young growth at 

 the tip of the stems bright yellowish-green. The cap- 

 sule in both mosses is sharply four-angled, almost 



