278 



PLANT LIFE. 



the filamentous algae and fungi (figs. 307, 308). In the 

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





-o° 





Fig. 308. — Sex organs of water flannel (I'aucheria 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. />), when og- becomes the ovary. B, 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 ioo 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 J 



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. 



