Mr. Bkown un Lyellia, Leptostomum, and Buxbaumia. 579 



By these lines also S. squarrosum is readily distinguished from 

 Octoblepharum, in which the apparent number of teeth is the 

 same : for in Octobkpharum each tooth has only a single pellucid 

 line; and hence its affinity to certain species at present referable 

 to Weissia, with a nearly similar habit and sixteen distinct teeth, 

 whose axis is not perceptibly pellucid. 



Weissia splachnoides differs from the other SplachnecE in having 

 sixteen equidistant teeth; but as these teeth, according to the 

 indication of the pellucid axis, are double, the arrangement may 

 be compared with that of Tayloria and Systylium, in which the 

 separation into thirty-two is complete, and the sixteen pairs equi- 

 distant. It agrees, however, also in this respect with Grimmia and 

 with several species of Weissia : but in other important characters, 

 as well as in habit, it is evidently related to Splachnum, and offers 

 perhaps one of the best examples of the importance of the male 

 flowers in distinguishing natural genera. 



Even Tetraphis pellucida may be cited in proof of the same pre- 

 vailing number in the peristomium; each of its four teeth, when 

 highly magnified, appearing to have seven longitudinal striae, 

 which, according to this test, would make the real number thirty- 

 two; a structure contributing to fix the place o( Tetraphis in the 

 natural series between Splachnum and Orthotrichum. 



observed it of the same form in specimens from Madagascar. There seems, therefore, no 

 reason to doubt that these two mosses differ materially even in this part of their structure j 

 and as other differences, of at least equal importance, also exist, both in the peristomium 

 and male flowers, Octoblepharum serratum, whose habit is nearly that of Splachnum, may 

 be distinguished both from that genus and from Octoblepharum by the following characters. 



. ,. Orthodon. 



Fl. Fem. termmalis. 



Peristomium simplex, octodentatum, dente singulo striis tribus longitudinalibus instructo 



(ideoque e quatuor coalitis composito). 



Calyplra mitriformis (4-fida, pilosa). 



FL Mas terminalis, discoideus, 



VOL. XII. 4 F Better 



