ADAPTATIONS FOR INTERCROSSING. 



229 



451, or better in Fig. 454, where the dotted lines indicate its 

 original position ; and first the end of the st3'le, tipped with 

 its stigma, is pushed forward, and then the anthers come into 

 view. The flowers are visited by humble-bees, and sometimes 

 b} r hone}--bees. In searching for nectar at the base of the flower, 

 they probably push forward into the space under the arching 

 keel, and by slightly elevating dislodge its apex ; when first the 

 stigma and then the anthers are brought against some portion 

 of the insect's body, and against the same portion in succeeding 

 blossoms, thus effecting cross-fertilization. This rationally ex- 

 plains a remarkable adaptation, which seems to be not otherwise 

 intelligible. 



419. Special Adaptations. Two of these, each peculiar to 

 the genus, may here be referred to. In Kahnia-blossoms (Fig. 



455-458), the anthers discharge the pollen through a small 

 orifice at the apex of each cell, in this respect agreeing with 

 Rhododendrons and their other relatives ; but 

 none of them utilize this family peculiarity in the 

 manner of Kalmia. In the flower-bud, each of the 

 ten anthers is lodged in a small cavity or pocket 

 (externally a boss) of the corolla, in a vfay analo- 

 gous to that in which the keel of Apios is lodged in 

 the tip of the standard (418) : the expansion of the 

 border of the corolla in an thesis curves the fila- 

 ments outward and backward ; and when the bowed 

 stamens are liberated by rough jostling they fly up elastically, 

 and the pollen is projected from the two orifices. Some pollen 

 may possibly be thrown upon the single small stigma at the 

 tip of the st}ie, which rises much above the stamens. But the- 

 anthers are not dislodged when undisturbed, at least until 

 after the elasticity of the filaments is lost : they are dislodged by 

 humble-bees, which circle on the wing over the blossom, the 



FIG. 455. Vertical section of a flower-bud of Kalmia latifolia, showing the anthers 

 1 xlged in the pockets of the corolla. 456. Expanded flower, with towed stamens 

 457. Vertical section of the same, 458. A stamen, enlarged. 



