476 



BOTANY 



PART II 



is attached to the substratum at its base or on the under side by means 

 of rhizoids, thus repeating the vegetative structure of many Algae. In 



J] 



FIG. 432. Funaria hygrometrica. A, Germinating spore ; ex, exine. B, Protonema ; kn, buds ; 

 r,' rhizoids ; s, spore. (Magnified. After MULLER-THURGAU.) 



the higher Hepaticae, on the other hand, and in all the Musci, there 

 exists a distinct differentiation into stem and leaves (Figs. 449, 456). 



Khizoids spring from the 

 lower part of the stem. 

 True roots are wanting 

 in the Bryophytes, 

 which thus do not attain 

 a higher grade of organi- 

 jr sation than the differenti- 

 ated thallus already met 

 with among the Brown 

 Algae, for example in 

 Sargassum. The stems 

 and leaves of Mosses are 

 also anatomically of a 

 simple structure; if 



FIG. 433. Marchantiapolymorpha. A, Nearly ripe antheridium Conducting strands are 

 in optical section; p, paraphyses. B, Spermatozoids. p regen t they are COttl- 

 (A x 90, B x 600. After STRASBURGER.) 



posed merely ot simple 



elongated cells. The sexual organs (antheridia and archegonia) are 

 produced on the adult, sexual generation ; in the thalloid forms on 

 the dorsal side of the thallus ; in the forms with stem and leaves at 

 p the apex of the stem or its branches. 



