THE FLOWER AND INSECT-POLLINATION 157 



are not all alike, and this tendency is chiefly noted in connec- 

 tion with the corolla. Attention has been called to the irregu- 

 larity of such flowers as the sweet pea and the snapdragon 

 ( 81, p. 133), the two kinds of irregularity they represent being 

 characteristic of certain large families (Fig. 103, C, D, and E). 

 In addition to these, attention should be 

 called to the irregularities called spurs 

 (Fig. 103, E), which are conspicuous 

 in orchids (Fig. 128), larkspurs, etc., and 



FIG. 125. Snow- 

 flake (amaryllis 

 family), with 

 epigynous flow- 

 ers. After 

 STRASBURGER. 



FIG. 126. Rose acacia: A, keel projecting from calyx 

 (the other petals removed) ; B, protrusion of tip of 

 style when keel is depressed ; C, section showing posi- 

 tion of parts within the keel. After GRAY. 



to sacs or pouches, such as appear in the lady slippers. 

 These spurs and sacs are always associated with the secre- 

 tion of nectar, for which many insects visit flowers. 



98. General statement. In the preceding sections, the 

 prominent departures from the condition of the primitive flower 

 have been noted. It should be understood that these depart- 

 ures occur in all sorts of combinations, and it is the varying 

 combinations that make the conspicuous differences among 



