34 



ACADEMIC BOTANY. 



with spiral threads ; these, in uncoiling, lift and disperse the spores ; 

 they are therefore called Elaters (Pig. 28). 



69. The Antheridia are flask-shaped, oblong, or 

 spherical. The antherozoids are ciliate and active. 

 The antheridia, like the archegonia, are contained 

 in special receptacles (Fig. 29, a). 



60. The spore now (except in Chara) develops 

 a Prothallus, or thalloid growth; this produces 

 the plant, with root, stem, leaf, and stomata. The 

 appearance of the Liverworts is often thalloid, 

 like that of Lichens; but the Liverworts are 

 always provided with chlorophy] and stomata 

 (Fig. 29, s, s). In the higher genera we see 

 stems with cedar-like foliage (Jungermannia). 

 Here are true roots also; but these are small, 

 consisting of simple fibres. The Liverworts love 

 damp, shady places; they are usually very deli- 

 cate ; and are green, violet, or brown. The stem- 

 growth is terminal ; giving to the second class of 

 Cryptogamia the name Acrogens, or Top-growers 

 (Gr. akron, top, summit). 



61. The Mosses (Fig. 30) have true roots, stems, 

 and leaves. They are cosmopolitan. Their 

 chief 

 use is 

 to make 



Fib. ii8. J 



—Marclian- anU CH- 



t\tfX, rich the 



spores. soil. Their colors are 



green and brown, rarely white; 



leaves simple, 1-nerved. Stems 



dt first simple, then giving off 



branches called innovaiions. The , y">- 29.— vert. sec. of a receptacle of 



IT, . « . -I Liverwort {Marchantw): a, a, ravities 



prothallus is COnierVOld. left by antheridia; c, c, air-chambers; 



8, 8, Stomata. 



Here the nucleus, after fertilization, 

 grows so rapidly that the archegonium is ruptured transversely, its 

 upper part being carried up by the nucleus ; this upper part is the 

 Calypira, or Cap (Pig. 30, c). The lower part of the archegonium 

 remains as a little sheath (Vaginula) around the base of the nucleus, 

 this base being a slender Seta (L. bristle). The seta elongates (still 

 capped by the calyptra) till it attains its full height j then its upper 



