I 



ORDERS OF MOSSES 251 



phyto elongates it carries up the remains of the distended 

 archegone as a Uttle cap (calyptra). 



445. The spores, which are round or angular cells 

 containing protoplasm, chloroplasts, oil-drops, etc., 

 germinate quickly upon moist soil. Each spore pro- 

 trudes a tubular filament, which develops into a conferva- 

 like ])ranching growth of green cells, called the '^pro- 

 tonema." Upon this buds are event uall}^ produced from 

 which spring up the leafy stems, thus completing the 

 round of life. 



446. There are three orders of Mosses, including about 

 12,600 species, as follows: (1) Black Mosses (Order An- 

 dreas ales), composed of a few small and rare mosses 

 whose spore-cases open by four longitudinal slits; (2) 

 Peat-mosses (Order Sphagnales), composed of large, 

 soft and usually pale-colored plants, with clustered lat- 

 eral branches; they inhabit bogs and swamp}- places, 

 where they form dense moist cushions, often 

 of great extent. On account of pecuharities 

 in the structure of their leaves they are en- 

 abled to absorb and hold large quantities of 

 water, and for this reason they are exten- 

 sively used for "packing" in the transporta- 

 tion of living plants. They all belong to Fig. 127 — 

 the genus Sphagnum, and their spore-cases (Amirt<aeu and 

 open by a circular lid, leaving an unguarded 



opening (without teeth). In this and the preceding 

 order the stalk supporting the spore-case is an extension of 

 the gametophyte stc^n and not a part of the sporophyte. 



447. (3) True Mosses (Order Bryales) include the 

 great majority of the species of this class. They are 

 usually bright green (in a few genera brownish), and in 

 most instances live upon moist ground and rocks, or 

 upon the bark of trees; in a comparatively small number 



