134 HANDBOOK OF BRITISH MOSSES. 



gium. This Moss must be distinguished carefully from Hyp- 

 num lutescens. 



]0. HETEROCLADITJM, Br. $ Schimp. 



Sporangium and peristome of Hypnum. Leaves sliglitly 

 papillose at the back ; marginal cells short, subquadrate, cen- 

 tral cells elongated. 



The generic distinction of this pretty little group rests more 

 on the structure of the leaves, which is very different from 

 that of Hypnum, than on their dimorphism, a circumstance 

 which occurs in many true Hypna. 



1. H. dimorphum, Br. fy Schimp. ; stem procumbent, irre- 

 gularly pinnate ; stem-leaves spreading and recurved, obcor- 

 date, acuminate; branch-leaves suberect, roundish, ovate, ob- 

 tuse, all toothed and two-nerved ; sporangium oblong, curved, 

 cernuous ; lid conical. Hook. 8f Wils. t. xxxv. ; Grev. Sc. 

 Crypt. FL t. 160.; (Moug. 8f Nest. t. 627.) 



Alpine rocks, Ben Lawers. Bearing fruit in winter and 

 early spring. 



Dioicous ; forming little, intricate, yellow-green tufts. Stem 

 procumbent, irregularly pinnate; stem-leaves cordate or ovate 

 at the base, am plexicaul, acuminate, recurved; branch-leaves 

 and occasionally those of the upper part of the stem more 

 erect, ovate, roundish, obtuse or acute ; all finely toothed and 

 faintly two-nerved ; marginal cells, as also those at the angles, 

 subquadrate, short, with moderately thick walls; disk -cells 

 elongated ; paraphylla scattered, variously shaped, toothed or 

 palmate ; fruitstalk even, about 4 an inch long ; sporangium 

 oblong, curved, horizontal, with a short obtuse lid. 



2. H. heteropterum, Br. fy Schimp. ; stem procumbent, 

 branched, pinnato-ramulose, often flagelliform and rooting at 

 the tip ; stem-leaves spreading, subsecund, ovate, acuminate, 



