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BULLETIN 28&, U. S. DEPARTMENT OF AGRICULTURE. 



not occupied by the vexillum. Even though the base of the carina 

 is narrow it is able to return to its normal position shortly after being 

 bent downward. The alse are attached by their flexible claws to the 

 common tube. Before a flower opens the alse are pressed closely to 

 the carina, although as the flower matures they spread apart. The 

 staminal tube splits superiorly to admit the tenth free stamen. The 

 filament of this superior stamen lies along the side of the staminal 

 tube and therefore does not interfere with the proboscis of a bee 

 which is inserted to collect nectar. Nectar is secreted at the bases 

 of the stamens and accumulates in the staminal tube around the base 



Fig. 1. — Different parts of a red-clover flower: 1, Anterior view of flower; 2, posterior view of flower after 

 the vexillum lias been removed; 3, posterior view of flower, showing the carina, which has been forced 

 apart (twice the magnification of the other drawings); 4, right ala, from within; 5, right half of carina, 

 from without, the claws of 4 and 5 having been partly broken off; 6, the essential organs emerging from 

 the depressed carina; 7, longitudinal section of a flower, a, Calyx; b, tube formed by the partial union 

 of 9 filaments with the claws of the vexillum, alse, and carina; c, vexillum; d, concave part of the inner 

 side of ala; e, lower border of ala, bent outward; /, outward surface of ala; g, pouched swelling on the 

 baseofanala; ft, carina; «,style; k, superior free stamen; I, stigma; 77;, anthers; «, point of union between 

 alse and carina; 0, point of flexure of the carina; p, part of the upper border of ala, bent outward; q 

 downward extension of the vexillum; r, staminal tube; s, style; t, ovary. (After Muller in part.) 



of the ovary. The filaments which compose the staminal tube sepa- 

 rate in the hollow of the carina. Each filament bears a fertile anther. 

 The pistil is inclosed within the staminal tube, the upper part of the 

 style and stigma of which are inclosed with the anthers in the carina. 

 The stigma is situated slightly above the stamens in most flowers, 

 although in some the anther of the longest stamen is as high as the 

 stigma. 



When a bee inserts its proboscis into the staminal tube, it is inserted 

 between the vexillum and the carina. In doine this the carina and 



