COXCERNING CLOVER. yj 



capital handed on to them by the mother-plant. But what will feed a 

 seedling will feed an animal as well ; and it is just these rich little 

 beans in the clover-pod which give it all its dangerous value as a fodder 

 for cattle. Hence, in the wild state those clovers which have their 

 seeds least protected are most likely to be eaten off and killed down 

 by birds or animals, while those which have them most protected are 

 most likely to survive and become the parents of future generations. 

 Here, then, we have the basis upon which natural selection can act in 

 differentiating the primitive ancestral clover into various divergent 

 species. Whatever accidental variation happens to give any particu- 

 lar clover protection for its seeds in any special habitat will certainly 

 be preserved and increased, while all opposite variations will be cut off 

 and demolished at once. So far as their foliage and their flowers are 

 concerned, the clovers as a body are practically in a state of stable 

 eqiiilibrium ; so far as their fruit and seeds are concerned, they are 

 still undergoing modification by natural selection. 



Clearly to illustrate this fundamental point, let us first look at some 

 neighboring and closely allied plants, which are not exactly clovers, 

 but which resemble them in almost all important particulars. These 

 also show the same devices for specially protecting their seeds and 

 pods from birds or animals. Take, for example, the genus of the 

 medics. These are mostly small greensward plants, with trefoil leaf- 

 lets like the clovers, but with the flowers in rather tall, one-sided spikes 

 or loose bunches. Their pods are usually long and many-seeded, but 

 they have this curious peculiarity, that instead of growing straight 

 like that of a pea or bean, they coil up spirally like a snail-shell. When 

 ripe they fall off the plant entire, and thus defeat the hopes of birds 

 and other creatures which wait patiently for the opening of the pods. 

 The simpler medics, such as the agricultural lucern, have smooth, 

 spiral pods alone, and therefore they can be employed successfully as 

 fodder for cattle. But this, which proves an advantage from the point 

 of view of the farmer, is naturally a disadvantage from the point of 

 view of the plant in a wild state, because it insures the seeds being 

 eaten ; and hence the more developed and weedy medics have ac- 

 quired stout protective prickles, fringing their globular spirals, and 

 making them very distasteful morsels to cows or horses. We have 

 two such prickly medics in England, one closely coiled and rolled 

 round like a ball, and thickly set with curved hooks ; the other loose 

 like a corkscrew, with two rows of sharp bristles at the adjacent edges ; 

 and both these, as I learn from farmers, are extremely objectionable 

 weeds in meadows, rendering the hay almost uneatable. Indeed, I am 

 assured that cattle will never touch even fresh meadow-grass contain- 

 ing them except when absolutely driven by hunger. It is noteworthy 

 that our two doubtfully native smooth medics (hicern and nonesuch) 

 both grow naturally in rough, dry places, and are only largely found 

 as " artificial grasses " — that is to say, were introduced and maintained 



