14.6 HETEEOSTYLED TBIMOEPHIC PLANTS. Chap. IY 



are a little upturned, so that they may be brushed by 

 the lower hairy surfaces of the insects' bodies. The 

 shortest stamens which lie enclosed within the calyx of 

 the long- and mid-styled forms can be touched only by 

 the proboscis and narrow chin of a bee; hence they 

 have their ends more upturned, and they are graduated 

 in length, so as to fall into a narrow file, sure to be 

 raked by the thin intruding proboscis. The anthers of 

 the longer stamens stand laterally farther apart and are 

 more nearly on the same leyel, for they have to brush 

 against the whole breadth of the insect's body. In 

 very many other flowers the pistil, or the stamens, or 

 both, are rectangularly bent to one side of the flower. 

 This bending may be permanent, as with Lythrvm 

 and many others, or may be efi'ected, as in Bictam- 

 nus fraxinella and others, by a temporary movement, 

 which occurs in the case of the stamens when the 

 anthers dehisce, and in the case of the pistil when 

 the stigma is mature ; but these two movements do 

 not always take place simultaneously in the same 

 flower. Now I have found no exception to the rule, 

 that when the stamens and pistil are bent, they bend 

 to that side of the flower which secretes nectar, even 

 though there be a rudimentary nectary of large size 

 on the opposite side, as in some species of Corydalis. 

 When nectar is secreted on all sides, they bend to 

 that side where the structure of the flower allows the 

 easiest access to it, as in Lythrvm, various Papilio- 

 naceae, and others. The rule consequently is, that 

 when the pistils and stamens are curved or bent, the 

 stigma and anthers are thus brought into the path- 

 way leading to the nectary. There are a few cases 

 which seem to be exceptions to this rule, but they are 

 not so in truth ; for instance, in the Gloriosa lily, the 

 stigma of the grotesque and rectangularly bent pistil 



