THE FLOWER. 325 



The nectar is secreted by small glands at the base, on the in- 

 side of the tube formed by the cohesion of thenine inferior fila- 

 ments, and accumulates around the base of the ovary. In the 

 center is the pistil, the style of which curves upwards, carrying 

 the stigma a little beyond the anthers. The tenth stamen is free, 

 and for most of its length is turned to one side, making it 

 quite easy for the long tongue of a bee to reach the nectar. 



In the words of Miihler, " If now a bee inserts its proboscis 

 beneath the vexillum, while it clings with its fore legs on to the 

 alae (which is coherent with the carina) resting its middle and 

 hind legs on a lower part of the inflorescence, the carina and 

 alae are drawn downwards, and the stigmas and anthers are 

 thrust up against the under side of the bee's head; the stigma, 

 standing highest, receives the pollen brought by the bee, and in- 

 stantly afterwards the anthers dust the bee with fresh pollen. 

 Cross-fertilization is thus insured; self-fertilization may take 

 place as the bee draws back its head, but is probably neutralized 

 and superseded by the immediately preceding cross-fertilization. 



" In order to reach the honey in this way (to the bottom of the 

 tube) an insect must possess a proboscis at least 9 to 10 m. m. long. 

 The pollen is accessible to all insects which can press down the 

 carina ; and such insects, whether they reach the nectar or not, 

 will perform cross-fertilization." 



Bumble Bees a Great Help in Fertilizing Red Clover. 

 The writer, as well as some of his students, has made many ex- 

 periments which help to prove the truth of the above heading. 



FIG. 129. IVf/oKum pratense, L. 



1. Flower, from below. 



2. Ditto, from above, after removing the vexillum. 



3. Anterior part of flower, twice as much enlarged ; the edges of the earina have 

 been forced apart. 



4. Right ala, from within. (The claws of 4 and 5 have been broken short off.) 



5. Right half of the carina from without. 



6. The essential organs emerging from the depressed carina. 



a, calyx; h, tube formed by the coalescence of the nine filaments with the claws of 

 the vexillum, alee, and carina; c, vexillum; f?, concave part of the inner side of the 

 ala; e, lower border of ala, bent outwards; /, outward surface of ala; 0, pouched 

 swelling on the base of the ala; ?i, carina: i, style; fe, superior free stamen; I, stig- 

 ma; m, anthers ; n. point of union between alae and carina ; o, point of flexure of the 

 carina; p, part of the upper border of the ala, bent outwards; g, downward extension, 

 of vexillum. (Mtihler.) 



