2/8 



PLANT LIFE. 



the filamentous 



algae 



and fungi 



(figs. 307, 308). In the 



thallus of multicellular algae it may be the terminal cell of a 



A 



7) 



-2. 



*~& 



- . // o VcT '";^ 

 D^-^o'Vj-yo.o- 



o^p ? qV 



;6V 



-Qik. 



FIG. 308. Sex organs of \\ater flannel (I'aucJieria sessilis). A, a portion of filament 

 with two lateral branches, a, og. In a the spermary has already been divided from 

 the body cavity by a partition wall. In og, a partition will form at juncture with main 

 axis (see fig. B), when og becomes the ovary. />', the ovary, mature, having opened 

 and extruded si, a portion of the protoplasm. What remains is the egg. The chloro- 

 plasts have accumulated, leaving a clear receptive spot opposite entrance of ovary. C ', 

 sperms, which escape at maturity from A, a. D, ovary with egg about to be fertil- 

 ized; the sperms have collected at the opening. A, B, D, magnified about 100 diam. 

 C, magnified much more (about 350 diam. ?). A, D, after Sachs ; B, C, after Prings- 

 heim. 



branch or, in the leaf-like forms, a cluster of surface cells. 

 In Fucus the spermaries (figs. 309, 310) are terminal cells 

 of much-branched hairs which 



develop from the surface cells 

 of a narrow -mouthed pit like 



FIG. 309. 



FIG. 310. 



FIG. 309. A portion of a branched hair from a conceptacle of bladder wrack (Fucus 

 vesiculosus). The darker cells are the spermaries. Magnified 160 diam. After 

 Thuret. 



FIG. 310. Spermaries of Fucus vesiculosus, showing the escape of the sperms. Magni- 

 fied 350 diam. After Thuret, 



