56 



OBJECT LESSONS IN BOTANY. 



156 157 158 159 



A leaf (Fig. 155), a sepal (Fig. 156), a petal 

 (Fig. 157), a stamen (Fig. 158), and a pod (pis- 

 til, Fig. 159) of Draba arabizans, placed side 

 by side for comparison. 



The central organ (or organs) is the pistil. We now propose 

 to notice the form of the stamens. 



100. The stamen may 

 be compared to the leaf. 

 Its slender, thread-like 

 stalk is the filament, an- 

 swering to the petiole of 

 the leaf {f^ip). Its head 

 {a) is the anther^ answer- 

 ing to the blade. More- 

 over, the anther contains 

 within its cells many dust- 

 like particles called j9oZ- 

 len. When the cells burst the pollen escapes. Thus it ap- 

 pears that the stamen consists of three members. See them 

 illustrated in this figure (161) of a stamen of the Morning- 

 Glory. 



101. The filament is nsnally of a thread-like form (as its 

 name, from the Latin jllum^ a thread, implies), longer than 

 the anther, and more or less elastic. But the filament is no 

 more necessary than the stem of a leaf, and is often wanting. 



102. Tlie anther is an oblong body at the top of the fila- 

 ment, consisting of two hollow lobes joined to each other 

 and to the filament by the co7inectile (c), which answers to the 

 midvein of the leaf. The two lobes are usually marked along 

 their outer edge by a sea77i, which at length opens into the 

 cells. This opening, however it takes place, is called the 

 dehiscence. If there be no filament, the anther is sessile. 



99. How many kinds ? Situations of the two kinds respectively t 



100. How does the stamen compare with the leaf? Specify the three mem 

 bers of the stamen. 



101. Describe ihe filament. 102. The anther; the dehiscenc«. 



