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NATURE-STUDY REVIEW [11:5— May, 1915 



white hairs or awns. The plants are small and grow in dry places, 

 around ledges and on dry knolls. In the East it is common at low 

 altitudes and in Colorado it is common almost to the summit of 

 the continental divide up to io,ooo feet. P. juniperinum is rather 

 lighter green than the other species and has larger capsules than 

 in P. piliferum and its leaves lack the white awn. It often grows 

 around the more moist borders of patches of piliferum and inter- 

 mingled with it. Although the Hair-caps are a pest in old grass 

 land they with the lichens are valuable soil formers for forest 

 growth. 



Fig. 4. Capsules of P. piliferum X5. 



It is very interesting to take a fully ripe and dry capsule of one 

 of the Hair-caps and after removing the lid by gently poking it 

 with a pencil point or other similar implement, gently knock on 

 the side of the capsule. The spores will rattle out in tiny clouds 

 like microscopic pepper from a tiny pepperbox. 



Besides the plants bearing capsules and the sterile plants one can 

 easily find rather short plants ending in tiny rosette. These are 

 so-called "male plants" which produce the tiny swimming anthero- 

 zoids; these have to swim in rain or dew to the summit of the 

 female stems and fertilize the egg cell produced there in order to 

 produce any spores. 



That they are ever able to do this seems a miracle. In some 

 species at least fertilization takes place in the early spring when 

 everything is moistened with the melting snow. 



