20 MOSSES WITH A HAND-LENS 



KEY. 



J. Leaf margins serrate, not infolded 2. 



Leaf margins entire, thin and infolded 4. 



2. Capsule four-angled 3* 



Capsule ovoid, obscurely 4- to 6-angled, beak long gracile. 



3. Capsules cubical, beak short commune. 



Capsules much longer than broad, beak long, neck taper- 

 ing Ohioense. 



4. Plants of dry situations, small leaves with long white 



awns -. piliferum. 



Plants larger, leaves without white awns 5. 



5. Plants of lowlands without felted radicles; capsules 3 mm 



to 5 mm long juniperinum. 



Plants of alpine or subalpine regions; stems covered with 



a dense felt of radicles, capsules 2 mm. to 3 mm. long, strictum. 



Our species are readily divided into two groups, as shown 

 in the key. One with serrate plane margins and the other with 

 margins thin and infolded, not serrate except at the extreme 

 apex. The plants are so large and the characters so well de- 

 fined that there will be no need to make use of microscopic char- 

 acters except perhaps in the case of P. gracile. These species 

 are all earth-growing. 



P. COMMUNE L., Common Hair-cap, is our largest moss, 

 sometimes having stems a foot long, although usually much 

 smaller. It is one of the most widely distributed of plants, 

 being found in all parts of North America, in Europe, and in 

 Asia. It is also one of the very few mosses put to some 

 economic use. The Laplanders use it to stuff pillows and beds. 

 In England it is sometimes used for brooms. 



A decoction of this plant was formerly much used to aid 

 in the growth of the hair in accordance with the curious old doc- 

 trine of signatures which taught that the medicinal uses of 

 plants were shown by their shape and structure; e. g. cordate 

 leaves were supposed to be good for the heart and Hair-cap 

 Mosses for the hair. 



The leaves of the Common Hair-cap are very thick and 

 strong, with a thinner clasping base and serrate margins. The 

 young sporophytes appear in late autumn or early spring and 

 the capsules mature in June or early July. 



The Common Hair-cap is variable in nearly all its parts. 

 The var. perigoniale is a form with very long whitish membra- 

 nous and long-awned perichsetial leaves. The var. uUginosum 

 has the leaves sprcading-recurved when dry; the stems more 

 slender and less rigid than usual. 



P. Ohioense R. &. C, Ohio Hair-cap, without the capsule, 

 is not readily distinguished from the Common, as leaves and 



