ACROGENS. 



193 



ing a multitude of particles emitted upon the application of 

 water ; and thecoo or hollow urn-like cases, covered by a 

 calyptra, closed by a lid, within which are rows of processes, 

 called the peristome ; the centre of the theca occupied by a 

 columella. Sporules, when germinating, protruding confervoid 

 filaments, which afterwards ramify, and form an axis. 



USES. Unknown. 



TYPICAL GENERA. Hypnum, Bryum. 



312. Jungermannia bicuspidata (Jungermanniacece). 313. Peristome of Tortula 

 mralis (Muscaceae). 314. Theca of Ceratodon purpureus (Muse.) 315. Supposed 

 representatives of sexual organs in Meesia longiseta (Muse.) 316. Bryum roseum 

 (Muse.) 318. Peristome of Octoblepharum albidum (Muse.) 319. Apophysis and 

 theca of Splachnum luteum. 



189. Andraacea. Branching moss-like plants, with im- 

 bricated leaves. Thecse with a calyptra, splitting longi- 

 tudinally into four valves. Peristome 0. Spores attached 

 to a central columella. 



USES. Unknown. 



TYPICAL GENUS. Andrsea. 



190. Jungermanniaceee. Creeping moss-like plants, either 

 with imbricated leaves, or with the leaves and axis all fused 

 into one. Thecse without an operculum, 4-parted, or 2-4- 

 valved. Spores mixed with elaters. 



USES. Unknown. 



TYPICAL GENUS. Jungermannia. 



