INTRODUCTION TO CRYPTOGAMIC BOTANY. 485 



are not fastigiate. The characters are, however, very incon- 

 stant even in the same species. Grimmia apocarpa^ is 

 abundant in both hemispheres, and appears both in Kumaon 

 and Mendoza ; other species affect equally the temperate 

 realms of either hemisj)here ; but a few only are tropical or 

 local. 



12. Ptychomitriei, Bv. & So. 



Sporangium destitute of a tapering base ; calyptra smooth, 

 furrowed, its apex subulate ; primary teeth not more than six- 

 teen ; cells of leaves punctiform, not papillate. 



536. This small tribe, included by Montague in Orthotri- 

 chei, differs from Grimmiei in the furrowed calyptra, and from 

 Orthotrichei in the texture of the leaves, smooth subulato- 

 calyptra, and in the sporangium not tapering at the base. The 

 spore-sac, moreover, is connected closely with the mitriform 

 walls of the sporangium. It consists of three genera — Cosci- 

 nodon, Glyjjho'mitriurii, and Ptychomitrium. The former is 

 remarkable for its cribrose teeth. PtycJiOTyiitriuni differs essen- 

 tially from Racomitrium in its plicate calyptra, and from 

 GlyphoTnitrium in its sixteen deeply bifid teeth, whereas those 

 of Glyphomitriwm are lanceolate and disposed in pairs. They 

 are confined, I believe, to the northern hemisphere. 



13. Octoblepharei, Mont. 



Sporangium regular ; peristome consisting of eight undi- 

 vided teeth ; calyptra conical, entire ; leaves white, with per- 

 forated cell walls, and imbedded chlorophyll cells. 



537. This tribe is remarkable for possessing (Fig. 99, a) the 

 colour and perforated cell-walls of Sphagnumii, without, how- 

 ever, the spiral thread. Moreover, those walls alone are per- 

 forated which are in contact with others, and not those which 

 are external. The resemblance, however, to Sphagnum is 

 more apparent than real, for the whole structure of the fruit 

 is different. 0. alhidum is a common inhabitant of the trunks 

 of trees in hot countries : the coast of Africa, central America, 

 Brazil, Oahu, Java, Mauritius, and the East Indies, are 



* I have marked in my notes as localities for this species. United 

 States, Greenland, Kumaon, Hermite and Falkland Islands, Mendoza, 

 New Zealand, Spain, Arct. Regions, Hymettus, and Europe in general. 



