I' LEGUMINOS.E 17:') 



explained by the winged stem, which, Ijeing wo wide, is 

 not entirely covered by the sheathing stipule. Conse- 

 quently if there were a lower limb on the outer side 

 it would be exposed. But though the stipule may 

 be correctly described as half- sagittate, it sometimes 

 shows a minute tooth where the other barb would have 

 been, indicating that it is descended from ancestors 

 which had a barb on each side.^ In L. pratensis and 

 L. maritimus, on the contrary, the petiole is round, the 

 wings lie one on each side and are fully covered by the 

 stipule of the preceding leaf. 



L. sylvestris. — The flower is unsymmetrical. The 

 left honey gland and the passage leading to it are larger 

 than those on the right, and it is remarkable that when 

 bees bite through the flower to get at the honey, which 

 they often do, they always attack the left side. Either, 

 therefore, they have discovered the best place by biting 

 at first at random, or, which seems more probable, 

 having noticed the inequality when sucking the flowers 

 in the normal manner, make the opening on the left. 

 In either case the circumstance is very remarkable, 

 and Darwin regarded it as " the most remarkable case 

 of skill and judgment " on the part of the bees known 

 to him.^ 



L. Nissolia (Fig. 89) is another curious species. It 

 lives among grass in meadows and waste places, and 

 has lost altogether, not only the leaves, but also the 

 tendrils. Instead, however, of enlarged stipules, the 

 functions of the leaves are assumed by the leaf-stalks, 

 which are elongated, flattened, linear, ending in a fine 

 point, and, in fact, so like the leaves of the grasses 

 among which the plant lives that it is almost impossible 

 to distinguish it except when in flower. The stipules 

 are minute and very slender. For a weak plant grow- 

 ing among close grass a long linear leaf is, perhaps, 

 physically an advantage. Some of the flowers produce 

 seeds, and yet do not open. Sometimes the buds are 

 large, at others quite small. Though they are not true 



' Avebury (Lubbock), Bxids and Stipules. ^ Forms of Flowers. 



