306 ~——» Structural and Physiological Botany, ae 
- The Musci are divided into two sub-classes, as follow peas ieee 
1. SPHAGNACEA. Log-mosses. ae 
According as the Sphagnaceze grow in water or on a solid sub- - 
stratum, they form a filiform or thalloid pro-embryo. In the sporo- 
r, carps are produced two kinds of 
spores; the larger are called 
macrospores, the smaller mz- 
crospores ; the former only ger- 
minate. The mode of growth } 
is shown in Fig. 431. [This Ave 
section includes the single genus 
Sphagnum. | 
=—— = aN aN 
A 
SS 
——= 
Fic.. 431.—Sphagnum acutifolium; I. part of the stem Fic. 432. — Splach- 
with two sporogonia a and four antheridial receptacles 4 num anipullaceunt 
-(after Schimper, x- 3); II. an antheridial receptacle | (Acrocarpi; magni- 
separated, with-the perigonial leaves removed from the fied). : 
lower part so as to expose the stalked globular antheridia 
(more strongly magnified). 
2. BRYINEEZ. True Mosses. 
Pro-embryo always filiform (protonema) ; only one kind of spore. 4 
I. Schizocarp~t or Andreeacee. ‘The ripe theca opens by four longi- ae . : 
tudinal slits (Fig. 4209). | ae ieee" 
2. Cleistocarpi or Phascacee. [The roundish theca ruptures the 
calyptra laterally, without raising it up as acap; no operculum,] = Phy 9) 
= 
«7 
