100 



MOSSES WITH A HAND-LENS 



grow intermingled with the archegonia (difficult for the lens). 

 The capsules mature in May and June, and as the antheridia and 

 archegonia are ripe at about this time, it must take the plant 

 a full year to mature its spores ; for this reason the leaves at the 

 base of the seta are often badly torn and decayed. 



B. BIMUM Schreb., the Red-stemmed Bryum, is another com- 

 mon species, growing on wet cliffs and in swamps. It is known 

 by its large size (2-6 inches) and the dense felt of red-brown 

 radicles that cover its stem. The leaves are rather distant, 1-12 

 of an inch or more long, plainly bordered, with costa percurrent 

 or excurrent, and red in old leaves. This species is exceedingly 



variable in size and gen- 

 eral appearance and one 

 who has collected it several 

 times cannot feel sure that 

 he will recognize it the 

 next time he finds it. 

 The spores mature in mid- 

 summer. 



B. DUVALLI Voit., the 

 Winged Bryum, is a rare 

 plant growing in elevated 

 swamps, but is so peculiar 

 as to be easily recognized 

 even when sterile. The 

 stems are slender and weak 

 with leaves very far apart, 

 much farther than the cut 

 would indicate, and so 

 strongly decurrent as to 

 make the stem appear 

 winged. They are scarcely 

 margined, and the costa is 

 not excurrent. 



POHUA NUTANS (Schreb.) Lindb., the Nodding Byrum, is 

 one of the mosses most frequently sent me for determination. 

 It grows everywhere in moist or swampy places on peaty soil, 

 rotten wood, etc. The plants vary from ^ to 2 inches in height, 

 rarely over an inch as I find them. The upper leaves are long 

 and narrowly lanceolate, faintly serrate at apex, and not mar- 

 gined. The costa is strong and ends below the apex. With the 



FIGURE 43- Portion of stem of Bryum 

 Duvallii much enlarged (From Bry. 

 Bur.). 



