LEGUMINOSAE 



323 



flower mechanism as similar to that of V. Cracca, except as regards the nature 

 of the brush arrangement. For here the style (2^ mm. long) bears two brushes, 

 immediately beneath the stigma. They are completely separate, about 1 mm. long, 

 and respectively situated internally and externally. The inner brush consists of 

 a single row of short hairs slanting upwards, while the outer one is composed 

 of hairs which radiate obliquely upwards towards the stigma, and enclose a plate- 

 like depression. The anthers dehisce when the flowers have attained a considerable 

 size, shed their pollen into a swelling at the tip of the carina, and are then retracted. 



Access to the nectar is more difficult than in V. Cracca, for the petals are 

 thicker and firmer, the calyx-tube surrounds their claws for a greater distance, 

 and the vexillum is tumid at the entrance to the nectar-passage, which is bounded 

 by it and the alae. In addition to this, the arms of the alar levers, which depress 



Fig. 106. Vicia septum, L. (after Herm. Miiller). (i) Flower seen from the front. (2) The same, 

 after removal of calyx and vexillum ; seen from above. (3) The same, after the alae also have been 

 removed ; seen from above. (4) The same, seen from the side. (5) Style with brushes and stigma, seen 

 from the side. (6) Brushes and stigma, seen from above. (7) Stamens and pistil of a bud. References 

 as in Fig. 105. 



the carina, are relatively shorter than in V. Cracca. Hence only powerful bees 

 (Bombus, Anthophora) are able to suck legitimately and effect crossing. The flies 

 and Lepidoptera which so often steal nectar from V. Cracca, sucking legitimately 

 but without benefit to its flowers, are here excluded, and this is a distinct advantage. 

 On the other hand, Bombus terrester regularly perforates the flowers from the side 

 and steals the nectar, although it possesses the requisite strength, skill, and length 

 of proboscis. Nectar is stolen by feebler bees with a shorter proboscis (Apis, Osmia 

 rufa) through the holes thus made. 



Visitors. The following have been observed by Herm. Miiller (H. M.) in 



Westphalia, Buddeberg (Budd.) in Nassau, and myself (Kn.) in Schleswig-Holstein. 

 A. Hymenoptera. Apidae: i. Anthophora aestiva Pz. J, skg. (Budd.); 

 2. A. pilipes F. $ and t>, skg. legitimately (H. M.); 3. Apis mellifica Z. 5, using the 

 holes made by B. terrester Z. (H. M., Kn.) ; 4. Bombus agrorum F. 5 and , skg. 

 (H. M., Kn,); 5. B. lapidarius Z. $ and , do. (H. M., Kn.) ; 6. B. muscorum F. $, 



Y 2 



