CHAPTER XVIII.

ON THE FARM SPECIES OF CLOVERS.

All the true clovers belong to the genus Trifolium, of which the following may be tabulated as agricultural species:—

(Flowers red or purple.)
1.	Trifolium pratense—Broad-leaved clover.
2.	Trifolium medium—Zigzag, or true “cow-grass” clover.
3.	Trifolium incarnatum—Carnation clover.
(Flowers pink.)
4.	Trifolium hybridum—Alsike clover.
5.	Trifolium fragiferum—Strawberry-headed clover.
(Flowers white.)
6.	Trifolium repens—Dutch clover.
(Flowers yellow.)
7.	Trifolium filiforme—Suckling clover.
8.	Trifolium procumbens—Hop clover.

1. Trifolium pratense—Meadow or broad-leaved Clover,—in its wild state, is too well known to need any lengthened description in order to its being understood. A careful examination of field specimens, however, will show that, even in the wild state, this plant is liable to run into numberless variations; thus, we may have the leaflets of one plant more or less ovate, whilst those of another may be broad and almost obcordate. In some we may see dense heads of purple flowers, varying in shade until almost white, whilst less dense heads of flowers and general variations in height, size, and luxuriance of the whole plant, are all circumstances in the natural history of this species in the wild state which will prepare us duly to understand the nature of the many forms of the plant which are found in cultivation. Of these we have, besides others, English, French, American, and Dutch sorts, which differ in such minor details, as a greater or lesser hairiness, or variations in the colour and size of the flowers, leaves, &c. The most important point connected with the broad-leaved clover is its permanency; some sorts scarcely maintaining a plant for two years, whilst others are said to be more or less perennial. This, however, is a matter which we conceive depends more upon the soil and the kind of cultivation than upon the sort; for, although all seedsmen supply two sorts, namely, Trifolium pratense and Trifolium pratense perenne, yet they run so much the one into the other, that it is oftentimes exceedingly difficult to distinguish them.

In order that the reader may see the differences and agreements of the three sorts,—1, Trifolium pratense (of the meadow); 2, Trifolium pratense (the arable plant); and 3, Trifolium pratense perenne (also of the arable),—we give their characters in parallel columns, on [p. 115].

CHARACTERS OF CLOVERS.

1. Trifolium pratense. ——— From a Natural Pasture.	2. Trifolium pratense. ——— From Messrs. Sulton’s Trial Grounds.	3. Trifolium pratense, perenne. ——— From Messrs. Sulton’s Trial Grounds.
Heads of flowers dense, proceeding from two leaves by a very short stem, of from 50 to 80 sessile florets of a more or less lilac or pink colour.	Heads of flowers dense, with from 70 to 120 sessile florets.	Heads of flowers somewhat lax, with from 50 to 100 florets, proceeding from leaves by an evident stem.

Calyx of 5 fine ciliated teeth—the lower of which is the longest—about half the length of the flower.	Calyx, much as 1.

Corolla, Standard with a long straight tube.	Corolla, much as 1.

Leaves trifoliate, more or less hairy; leaflets ovate, either broadly lanceolate, or notched at the apex; all having a more or less triangular white marking in their centre.	Leaves of 3 leaflets, more or less ovate, with the white triangular marking 3 times the size of 1, but less hairy.	Leaves of 3 ovate leaflets, with less distinct triangular spot than 2, clothed with silky hairs.

Stem solid, channelled or angular, purple.	Stem sometimes fistular, more or less channelled or ribbed, mostly free from hairs, purple upwards.	Stem variable, sometimes fistular mostly quite round and smooth sometimes; but not generally hairy.

Root descending, but considerably branched.	Root tapering with lateral branches.	Root as 2.

Whole plant more or less clothed with silky hairs.	Whole plant, smooth, compared with 1, still more or less hairy.	Whole plant, remarkable for its hairy leaves and generally smooth round stems.

Height from 5 to 8 inches.	Height 16 inches.	Height 18 inches.

Now, although the study of the characters, as here laid down with the specimens in our hand, may render it tolerably easy to distinguish the three forms here described, yet it must be confessed that whether we examine a series of the wilder plants from different positions, or different samples of the cultivated broad-leaved clovers, we shall find great variations; the principal of these will be discussed in another chapter: we may here, then, for the present leave this difficult subject of how to distinguish cow-grass and broad-leaved or red clover, with the observation that the common red clover is uniformly in flower two or three weeks before the other.

2. Trifolium medium (see [Plate])—Zigzag Trefoil—gets its English name from the peculiar bends in its stem, which being at alternate sides, make up the zigzag outline. The stems are rounded—not channelled,—mostly of a purple colour, and clothed with short hairs. The leaves are smooth, with elliptical—not emarginate—leaflets, sometimes, but seldom, with the white lunulate spot. The calyx is smooth. The heads of flowers are solitary, on very short footstalks; they are of a bright pinkish red hue, and not of the lilac colour of the common clover.

Trifolium medium.Zigzag Trefoil.

In its wild state the zigzag clover will be found in districts remarkable for the absence of lime, such as the sandstones. In the sandy deposits accompanying the coal in Wales, as also in Staffordshire, this is the prevailing form of clover. Hence, then, this species seemed to recommend itself for sandy lands, in which the common clover does not so well succeed; and we conceive that, as a consequence, it was brought into cultivation for this capability of “holding on” to such soils, which, if they will not grow the other kind, is considered clover sick. We have reason to think that the T. medium and T. pratense are not distinct species, but that the difference in their usual habitats has determined their difference in form, and we think that the T. pratense perenne of the seedsman is a form intermediate between the two: if so the position of the three may be expressed as follows:—

Trifolium pratense.Trifolium medium.
Trifolium pratense perenne.

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.”