LEGDMINOS.i: 157 



Ononis 



We have two species — one (0. arvensis, Rest-harrow) 

 is perennial, and often thorny ; the other (0. reclinata) 

 is annual, and the peduncle is jointed beneath the 

 flower. Ononis does not secrete honey, and conse- 

 quently there is no need for the separation of the 

 upper stamen, which in this genus is attached to the 

 rest. Again, in Ononis all the stamens are thickened 

 at the end; the outer ones, however, much more so 

 than the inner ones. The inner ones, on the contrary, 

 produce much more pollen than the others — a difference 

 of function which is even more marked in the Lupins. 

 The keel forms a tube, closed except at the end, where 

 there is a small orifice through which the pollen is 

 pressed. 



Both our species are somewhat variable. O. arvensis 

 is sometimes prostrate, sometimes erect, generally 

 clothed with short spreading hairs, and more or less 

 glutinous, but sometimes glabrous. The hairs are 

 either scattered or collected in two opposite lines. The 

 lateral leaflets are sometimes wanting. The plants are 

 usually spiny, but show much variation in this respect, 

 and some forms are unarmed. 0. reclinata is slightly 

 hairy, often viscid. 



Medicago 



This is a large genus, of which we have in Britain 

 six species. Two are perennial, M. sativa (Lucerne), 

 with purple flowers, and M. falcata, with yellow flowers, 

 sometimes passing into blue or violet. The other four 

 species are annual. M. lupulina (Black Medick) has 

 one seed in the pod, the others several. M. minima is 

 downy, with nearly entire stipules. M. denticulata 

 and M. maculata are nearly glabrous. In M. denticulata 

 the pod has two to three loose spires, in M. macidata 

 it is nearly globular. The flowers secrete honey. 

 In some species the pods are round, flattened, and roll 

 along the ground like little green wheels, as in the 



