146 GROWTH AND WORK OF PLANTS 



the stamen sometimes remains attached to the base of the petal 

 when that is removed from the calyx tube. Four of the stamens 

 are set opposite the petals and four are alternate with them as 

 shown in the photograph of a dissected flower in figs. 106, 107. The 



Fig. 107. 



Flower of evening primrose with petals removed to show the four spreading lobes of the 

 stigma, and anthers beneath them. Petal at right, showing two stamens attached. 



filaments are strongly curved at the base, all in the same general 

 direction, with the concavity toward the axis of the spike. The 

 anthers are versatile, i.e., each anther is attached by one face 

 near the middle to the point of the filament, upon which it swings 

 loosely. The filament is attached to the outer face of the anther, 

 so that the anther faces inward toward the axis of the flower, and 

 is said to be introrse, or incumbent. The anther consists of two 

 pollen sacs (locules) which open by a long slit on the inner faces. 

 This takes place before the flower opens and the pollen is depos- 

 ited in great masses on the outer surfaces of the four lobes of the 



