23: 



PLANT LIFE. 



spore's, and much smaller ones, known rs microspores (fig. 

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

 plant, or gametophyte (■ 377), upon which, however, only 



Fio. 235. 



Ki<;. 



Fir,. 235 Pari ol two sporophytes ol .1 horsetail {Equisetum arvense). A, the 

 spring shoots, with sheath like whorls ol leaves below and crowded sporophylls above 

 «, summer shoots, much branched, with inconspicuous leaves; nutritive work all 

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



Fig. 236. — Three sporophylls from the flower of a horsetail {Equisetum telmntein), 

 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 



