THE TRUE MOSSES 



519 



341, II. — Umbrella-liverwort. ArchiKonio- 



phores (?) bearing ripe "fruit" (sporophytes), 

 the spore-cases of which aie seen projecting 

 beyond the curtains wliich protected them 

 while young. Two of the spore-cases have 

 burst showing the projecting elaters. (At- 

 kinson.) 



extending into the capsule is a column of somewhat elongated cells, 

 which is called the columella ' (Fig. 345, c, c). Breathing-pores at 

 the surface permit aeration of the inner cells. 



Hepatica^ are plants producing archegonia upon a mostly prostrate 

 and thalline gametophyte which may he variously lobed or branched 

 and often resembles a flattened leafy moss, but which generally has 

 well-contrasted upper and loiver surfaces; and there is a sporangium 

 geyierally dehiscing longitudinally and discharging its spores by means 

 of intermingled thread-like elaters. There are about 3,000 species. 



190. The true mosses (Class Musci). The name "moss" 

 is popularly given to any small, matted plant of soft texture 



^ Col-u-mol'la < L. diminutive of colnmna, a pillar. 



