CONCERNING CLOVER. 79 



intended to attract the fertilizing bees. The young flower-heads are 

 also inclosed in two papery wings or stipules, which effectually pro- 

 tect them from injury before they open. The petals are united into 

 a very long tube, accessible only (as before noted) to the humble-bee ; 

 and in New Zealand, where our European humble-bee is unknown, it 

 has been found necessary to import several nestfuls, in order to make 

 the acclimatized clover set its seed for agricultural purposes. But 

 the devices for the protection of the pod are here comparatively slight. 

 Each pod contains, as a rule, only a single seed, and it is externally 

 guarded simply by the wire-like calyx-teeth, which are long, thin, and 

 awl-shaped, and fringed on either side by a row of thick-set hairs. 

 The two lowest are longer than the others, apparently as a protection 

 against crawling insects. After flowering, the petals remain upon the 

 heads, turn brown, and inclose the ripening pod. These brown heads 

 of overblown flowers have such a dead, withered appearance that they 

 seem sufiiciently to deceive all intending depredators. As a whole, 

 the species seems to survive mainly because of its protected young 

 flower-heads, its special attractions for fertilization, and its habit of 

 inclosing the pods in the dry petal-tube. It should be noticed, how- 

 ever, that, though artificially propagated in meadows and pastures, it 

 would not probably be a very successful plant if left entirely to its 

 own devices. Man has intervened to give it his powerful aid by sow- 

 ing its seed, and by fencing it off from cattle, so that it has now be- 

 come, in spite of itself, one of our most abundant and ubiquitous 

 clovers. 



Next in order we may take a series of small, wild, purplish clovers, 

 closely allied to this cultivated type, but more specially adapted for 

 protection against animal foes. Of these the little knotted clover, 

 which grows in our dry pastures and banks, is an excellent simple 

 example. It is a small, tufted annual, often growing in very closely 

 cropped, sheep-eaten crofts, and therefore with an acquired habit of 

 creeping close to the ground, and spreading its foliage flat against the 

 earth. Its calyx-teeth are short and almost prickly, and its little knot- 

 ted heads grow so close in the angles of the leaves that even a sheep 

 has hard work to bite them off with his nipping front teeth. The 

 rough clover is another of these dwarf creepers, much like knotted 

 clover in general appearance, but even more prostrate, and with its 

 flower-heads still more closely wrapped up in the angles of the leaves, 

 whose wings or stipules almost completely inclose them. The great- 

 est difference, however, resides in the calyx, whose teeth here, after 

 flowering, become broader and stiffer, curve backward, and give the 

 whole plant a stringy, dry, innutritions look. This species or variety 

 also grows mostly on sheep-bitten banks, and manages wonderfully to 

 set its seed in spite of the manifold dangers to which it is exposed. 

 Boccone's clover, confined in Britain to the Lizard Promontory in 

 Cornwall, is a larger southern form of the same central type, closely 



