At all events, if this plant was ever distinct in cultivation, it has merged into broad clover forms; so that, if we are to possess it as a separate plant, it must again be grown from wild seed, and then, if it is to be kept pure, it must not be cultivated on clays or limestone, or, if our view be correct, it will soon lose its true distinctive characters.
3. Trifolium incarnatum—Annual Carnation or Crimson Clover—is a large species with oblong heads of flowers of a fine carnation colour, hence its common name of “Carnation Clover.” It is a native of Southern Europe, and is said to have been found wild at the Lizard, in Cornwall. As a cultivated plant, it has not long been introduced into England, where it has been much grown in the southern counties, as there it can be sown soon enough on the wheat stubbles with only just a simple harrowing-in, when it has time to make a plant sufficiently strong to resist winter; this soon makes growth in the spring, giving an early feed, or it may be mown; in either case it is off the land sufficiently early to allow of a late sowing of turnips: so that, where the climate will allow of it, we may snatch an intermediate crop by means of the carnation clover. It yields a large crop, but its feeding qualities, according to Dr. Voelcker, are somewhat inferior to those of the broad-leaved clover. It should be noted that varieties having white flowers are in the market, and of both red and white there are earlier and later sorts which may be useful for succession.
4. Trifolium hybridum—Alsike Clover—has, perhaps, got its specific name from possessing appearances and qualities intermediate between the broad-leaf and the Dutch clovers. This species has been introduced from Sweden, and its growth, duration, and feeding qualities certainly entitle it to rank high, and more especially for growth on some of the stronger soils. In our experience we have not found it to possess such eminent perennial habits as have been claimed for it. It thins very much after the second year, and almost disappears in three years, unless it be renovated by being allowed to seed, when the new plants by no means attain to the vigour of their parents.
5. Trifolium fragiferum—Strawberry-headed Clover—has been named from the strawberry-like form which its head, of enlarged coloured calyxes, assumes after flowering; its flowers are pinkish, but otherwise of much the same size and form as those of the Dutch clover, which latter it again approaches in its creeping habit and form of its foliage. It is, however, here mentioned only to point out the difference of its habits and indications when compared with the Dutch or white clover. The strawberry trefoil is a native of cold wet pastures, such as bear the name of “hungry clays;” when present in quantity it is not to be confounded with Dutch clover, which would indicate a sound fertile soil.
6. Trifolium repens—White Dutch Clover—is a plant of very general cultivation, both at home and in the States, and in both of which quarters of the globe it maintains its character with great constancy.
Dutch clover is a valuable pasture plant either in meadows or in seeds. In the former it is much increased by the addition of nitrates, soot, &c., with guano or superphosphate. As a plant, in seed mixtures, it is usually sown with other trifoliate plants and rye grasses, but if the soil be very light the Dutch clover may be increased or wholly used.
7. Trifolium filiforme—Small Yellow Clover—is one of the least of our small yellow-flowered division. It is a common native species occurring on the waysides, and has been brought into cultivation to only a limited extent, under the impression that its small herbage is suitable as a first bite for young stock, and hence the term “suckling clover” has been applied to it. It is of little value, and does not seem capable of being greatly improved. This species is often mistaken for the following, even by pretended botanists, but its lax head of smaller flowers will well distinguish it.
8. Trifolium procumbens is called by the botanist “Hop Trefoil,” from the fact that its dried head of persistent flowers[6] exactly resembles small bunches of hop strobiles (fruiting heads). The foliage is much like that of Medicago lupulina, nonsuch, or black medick, which is the “hop” of the farmer; but the whole plant of the true hop trefoil dries up so quickly under the sunshine, and is withal so wanting in succulency and quality, that it cannot be compared with M. lupulina as a fodder plant, and hence it is but little cultivated in the present day.
[6] Flowers are so called that remain enveloping the seed while it ripens, which they do in all the clovers.
There are other clovers which have been recommended for cultivation, but they are mostly foreign, and do not appear to possess those qualities which should lead us to prefer them before those in common use. There are, too, several additional wild clovers, but they possess no agricultural interest, unless, perhaps, as indicators of soil. The Trifolium pratense (Hare’s-foot Trefoil) is a pretty, wild species, native to light sandy soils, the seed of which is sold for growing “bedding plants.”