Mosses with Straight-haired Veils 



transparent; the veil is bell-shaped, more or less split at the base 

 and keeled or deeply grooved throughout, it may be naked or may 

 have a few straight hairs, a character which suggested the name 

 Ortbotrichum, from 6p@d<t, straight, and @pl, T/ot^o'?, hair. The 

 spore-cases are immersed or exserted on a short pedicel and have 

 usually, when dry, 8 to 16 grooves running lengthwise, but they 

 may be smooth. The pedicels are gen- 

 erally short with an enlarged base (vagi- 

 nule) crowned with a minute cup-like 

 sheath. The peristome is simple or 

 double, the outer consisting of 16 single 

 teeth or 8 pairs, with either no annulus 

 or a very narrow one. 



In all there are two hundred and 

 thirty-five species, fifty-seven being 

 found in North America. 



Orthotrichum strangulatum,Beauv. 



Habit and habitat. In small, loose 

 dirty-green tufts % of an mcn deep; on 

 trees, rarely on rocks. 



Name. The specific name strangula- 

 ium, strangled, refers to the constriction 

 under the mouth of the spore-case. 



Plant (gametopbyte) . One-quarter of 

 an inch long. 



Leaves. Linear lance-shaped from an 

 oblong base, keeled; apex pointed or 

 blunt; margins rolled back; cells, the 

 upper, round, small, close, with slight 

 protuberances; the basal, long and quad- 

 rangular. 



Leaves ai tie base of tie pedicel (peri- 

 cbcetial leaves}. Longer, erect, some- 

 what sheathing. 



Habit of flowering. Male and female 

 flowers on the same plant (monoicous). 



Veil (calyptra). Resembling a bish- 

 op's mitre (mitriform) furrowed and 

 nearly naked. 



Spore-case. Oblong egg-shaped, 



189 



\ 



Plant. 



Portion of peristome. w ith 

 two cilia and four teeth. 



O. strangulatum. 



