164 



BRITISH FLOWERING PLANTS 



up, and forms a sort of balloon serving for the dissemina- 

 tion of the small fruit. 



T. subterraneum. — In most clovers the head contains 

 from 50 to over 100 florets. In this, on the contrary, 

 only a few (3-5) florets become complete flowers. The 



Fig. 107. — Trifolmm sxibterraneum. Shoot showing buds at end, and three older 

 flower-heads which are tnrued down and beginning to bury themselves. 



others, proceeding from below upwards, are gradually 



reduced to stiff spines, forming a rigid pointed head. 



The complete florets stand upwards, 



but after they have flowered the 



peduncle bends over (Figs. 107, 108), 



turns towards the ground, and grows 



downwards, sometimes elongating to 



the extent of 6 or even 9 inches, 



forcing the . flower - head into the 



Fig. w?,.-THfoiium sub- grouud to a dcptli of | or |- inch, an 



fen-aneum. Flower-head, operation much facilitated by the 



slightly magnified. ■■■ , . . -, ■' 



peculiar construction and arrange- 

 ment of the imperfect florets. The florets are, as Darwin 

 has shown, no mere passive instruments. So soon as 

 the flower-head is in the ground they begin, commencing 

 from the outside, to bend themselves towards the ped- 

 uncle, the result of which, of course, is to drag the flower- 

 head farther and farther into the ground. In most Clovers 

 each floret produces a little pod. This Avould in the 

 present species be useless, or even injurious ; many young 

 plants growing in one place would jostle and starve one 

 another. Hence we see another obvious advantao-e in 

 the fact that only a few florets perfect their seed.^ 



^ Vaucher, nist. Phys. des Plantes d'Eiirope, vol. ii. 



