ANGIOSPERMS: TRILLIUM. 



223 



that it is made up of minute bodies which resemble spores ; they 

 are rounded in form, and the outer wall is spiny. They are in fact 



spores, 



the 



microspores 



of the trillium, and here, 

 as in the gymnosperms, 

 are better known as pollen. 



Fig. 291. 



Sepal, petal, stamen, and pistil of Trillium 

 grandiflorum. 



444. The stamen a sporo- 

 phyll. Since these pollen 

 grains are the spores, we would 

 infer, from what we have 

 learned of the ferns and gym- 

 nosperms, that this member of 



the flower which bears them is a sporophyll ; 



and this is the case. It is in fact what is called 



the microsporophyll. Then we see also that the 



anther sacs, since they enclose the spores, would 



be the sporangia (microsporangia). From 



it is now quite clear that the stamens 



belong also to the leaf series. They 



are just six in number, twice the number 



found in a whorl of leaves, or sepals, 



or corolla. It is believed, therefore, 



that there are two whorls of stamens in the flower of trillium. 



445. Gynoecium. Next above the stamens and at the center 

 of the flower is a stout, angular, ovate body which terminates in 

 three long, slender, curved points. This is the pistil, and at 



Trillium gran- 

 diflorum, with 

 the compound 

 pistil expanded 

 into three leaf- 

 like members. 

 At the right 

 these three are 

 shown in detail. 



