232 



PLANT LIFE. 



spores, and much smaller ones, known as microspores (fig. 

 241). Each kind, when it germinates, produces a sexual 

 plant, or gametophyte (^[ 377), upon which, however, only 



Fig. 235. 



Fig. 236. 



Fig. 235.— Part of two sporophytes of a horsetail {Eqvisetum arvense). A, the 

 spring shoots, with sheath-like whorls of leaves below and crowded sporophylls above. 

 />', summer snoots, much branched, with inconspicuous leaves ; nutritive work all 

 done by stems of these shoots. Two thirds natural size. — After Kerner. 



Fig. 236. — Three sporophylls from tlie flower of a horsetail iEquisetum telmatei«i) % 

 seen in different positions, s, the shield-shaped sporophyll ; st, its stalk attached to 

 the center of dorsal face ; sg-, sporangia. Magnified about 10 diam. — After Sachs. 



one sort of sexual organs is borne. The megaspores give rise 

 to plants bearing female organs only, the microspores to 



