108 



THE FLOWER 



p __- 



c - 



/ 



143. a, a stamen ; p, pollen sac 

 connective; ./", filament 



b, 



203. The pollen-bearing organ is the stamen (Fig. 143). 



Its parts are the stalk, called 

 the filament, and the anther, 

 containing the pollen in pollen 

 sacs. In the young condition 

 of the stamen four longitudi- 

 nal pollen sacs are found. 

 The whole mass of tissue 

 filling these sacs is finally con- 

 verted to pollen. At matu- 

 rity, if not before, the wall 

 between the two cavities on 

 the same side of the anther 



a stamen with the anther commonly disappears, leaving 

 cut through at the time of a single j)ollen sac in either 

 . ™^ ^^^ ^' half-anther. The middle part 



or axis of the anther between the two pouches thus formed 



is the connective. 



204. The pollen sacs open for the liberation of the pollen 

 usually by a slit along the groove running down each side 

 of the anther ; in Pyrola and other members of the Heath 

 family, by terminal pores (Fig. 144) ; 

 and in the Barberry by uplifting 

 valves (Fig. 145). And other modes 

 of dehiscence occur, suited to the 

 various means by which tlie pollen 

 is to reach its destination. 



205. The number of stamens is 

 often large, as in the wild Rose, the 

 Buttercup, the Magnolia, and the I4i, i^^. Stamens : 144 of 



■L ' ^ _ Pyrola, the anther 



Water Lily. In a few species there opening hy terminal 



is but one. Generally speaking, the p°-; \«; »[^Ba,.; 



number is small, not more than ten ; opening hy uplifting 



and, when small, usually definite for vahes. 



each species. For example, most grasses have three sta- 

 mens, most Mints four, the Violets five, and the true 

 Lilies commonly six. Each pollen sac produces a vast 

 number of pollen grains. And when the flowers borne 



