CROSS-FERTILIZATION, CONCLUDED 



243 



279. A flower of one of the common milkweeds 

 (aselepias) is shown in Fig. 231. An insect has 

 alighted upon it. If this insect were examined 

 after his visit he would 

 probably be found to be 

 carrying saddlebags (like 

 h) upon his legs or tongue. 

 The bags constitute the 

 pollen, and each bag com- 

 prises the entire content of 

 an anther locule. The han- 

 dle or caudicle of these 

 bags is attached in the 

 chink or slit of a gland 

 on the side of the stigma, 

 and the insect, by catch- 

 ing its legs in this chink, 

 drags out the bags and 

 carries them, with the gland, to other flowers. 



Fig. 231. 

 Pollination of milkweed. 



219a. Such masses of pollen (which occupy the entire locule) are 

 known as pollinia. Pollinia are characteristic of orchids and milk- 

 weeds, highly specialized plants of widely different families. 



280. The dalibarda is a low dewberry- like plant 

 (but resembling a violet) growing in woods in the 

 northernmost states. It is ' shown in Fig. 232. A 



normal showy flower is at a. 

 ever, there are clusters of 



At 6 and c, how- 

 seeds upon shorter 



