ARCHEGONIATES 



113 



of the stalk known as the foot. The capsule contains a central 

 axis of sterile tissue, the columella. 



275. When the spores germinate a branching green thread 

 (protonema) like an alga is developed. From this the moss 

 plants are formed by budding. By this protonema the mosses 

 may be distinguished from the liverworts. The mosses are 

 always holophytic and chlorophyll green. 



276. Order 1. — The SphagnacecB are the swamp mosses. They grow 

 continually upward while dying away at the base. The capsule is short 

 stalked and the foot is broad. A pseudopodium is formed by the elonga- 

 tion of the branch below the foot. The archegonium wall breaks and its 

 fragments remain at the base of the capsule. The capsule opens by a lid. 

 The columella is hemispherical. There is only one genus, Sphagnum, 

 with many species. 



277. Order 2. — The AndreacecE are usually found in small clusters on 

 rocks. The capsule is short stalked with a broad foot and is elevated by 

 a pseudopodium. The archegonium wall breaks around the base and 

 remains on the capsule like a cap (calyptra). The capsule opens by four 

 longitudinal slits. There is only one genus, Andrea. 



278. Order 3. — The Phascacece are small, simple mosses with persistent 

 protonema, and a short stalked capsule which does not open. The spores 

 are set free only by the disintegration of the capsule. 



279. Order 4. — The Bryince comprise most of the common mosses. In 

 these the capsule is long stalked (seta) with a foot. The archegonium 

 forms a calyptra. The capsule opens by a lid (operculum). On removal 

 of the operculum the edge of the opening of the capsule is seen to be pro- 

 vided with a fringe,, the peristome, which by hygroscopic movements 

 assists in the scattering of the spores. 



280. Branch III. Pteridophyta. — The ferns are ditleren- 

 tiated into true root, stem and leaf. Conducting and sup- 

 porting tissues in the form of fibro-vascular bundles occur, as in 

 the higher plants. The ferns are like the mosses in regard to the 

 structure of the gametangia and are hence archegoniata. Like 

 the mosses they also have a distinct alternation of generations. 

 The gametophyte, however, is reduced to an inconspicuous 

 thalloid structure (prothallium) or still farther to a minute 



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