CONCERNING CLOVER. 8i 



posed that all these questions are yet by any means finally solved. 

 The sole object of the present paper is to point out the common prin- 

 ciple running through the variations of the clover pattern, and to 

 suggest such partial explanations of their causes as have yet occurred 

 to a single observer. 



Suffocated clover is another of the tiny creeping types, apparently 

 protected for the most part against browsing quadrupeds. It is a wee 

 tufted form, with minute flowers stuck close in small dense beads, as 

 if gummed to the short stems, and very crowded along their course. 

 We may regard it as the last effort of a very degraded race to keep 

 up its existence in the most closely gnawed pastures, on sand or 

 gravel, where only very dwarfed and scrubby plants can escape de- 

 struction. The reader will notice that under such circumstances two 

 types of clover succeed, each in its own way. If the heads become 

 very small, close, and inconspicuous, or tightly pressed against the 

 wiry trailing stems, they escape the observation of browsing animals. 

 If, on the other hand, though tall and noticeable, they develop prickly 

 or stiffened teeth, they are rejected as unfit for food by the creatures 

 which devour the surrounding herbage. 



Reversed clover takes its name from a peculiarity which seems to 

 , be connected with its mode of fertilization, for it has its standard petal 

 turned outward, instead of inward as in all other clovers. The mean- 

 ing and object of this change I do not know ; but its most marked 

 feature is still one bearing upon preservation of the seed, for, after 

 flowering, the upper part of the calyx becomes much inflated, and is 

 traversed by large membranous veins. At the same time it arches 

 over the lower half, leaving three small teeth below, and two swollen 

 ones at the top, so as to form a sort of bladder-like capsule over the 

 concealed pod. In this case, again, the protection is obviously de- 

 signed against birds or insects. In the curious strawberry clover, 

 common among dry meadows and road-sides in Southern Britain, the 

 same device has been carried a step further. Each flower in the head 

 is here surrounded by a long involucre of lobed bracts, and, after flow- 

 ering, the calyx swells I'mmensely, so as to transform the entire head 

 into a compact globular ball of little bladders, each inclosing a single 

 pod. This arrangement has been popularly compared to a strawberry, 

 but it is much more like a raspberry, being a delicate pink in hue, and 

 composed of twenty or thirty small round capsules. The upper half 

 of the bladder is likewise thickly covered with fine down, doubtless 

 very objectionable to the skin of the tongue, and the whole is netted 

 and veined in the most delicate and beautiful fashion. Hardly any 

 other clover possesses so advanced a plan for protecting its little pod. 



Another type is presented to us by the large crimson clover, not 

 truly indigenous in Britain, but commonly cultivated for fodder in 

 the south of England. It is a soft, hairy plant, and, like other fodder- 

 clovers, it does not possess any very advanced protective device. Still, 



VOL. XXTIII. — 6 



