CHAPTER XIX.
ON THE VARIETIES OF RED CLOVERS.
The Trifolium pratense of botanical authors is remarkable for the great number of varieties it assumes, even in its wild growth; but these are exceeded in the number of cultivated forms: thus in any rich meadow we may make out several sorts which may be expected to be more or less permanent, whilst the market samples of seed will offer us several varieties for the different countries of America, England, France, Holland, Germany, &c.
The following are some of the more prominent of our native wild varieties:—
1. Trifolium pratense—Common Red Clover.—Head of pink; flowers, somewhat compact; leaves more or less broad; plant smooth[7] in proportion to its size, the smaller wild specimens being usually very hairy; stem more or less purple.
2. Trifolium pratense, var. pallidum—Pale-flowered Clover.—Head of very light pink; flowers large, full, and more rotund than 1, and almost double in size and in the number of its flowers; whole plant more or less hairy; stem green.
3. Trifolium pratense, var. album—White Clover.—Flowers white; herbage a very light green; in other respects much the same as the last.
4. Trifolium pratense perenne—Perennial Red Clover.—Flowers less compact than the common clover, whole plant having stems inclining to dark purple; leaves narrower.
[122]5. Trifolium pratense perenne, sub-var. pallidum—Pale Perennial Clover.—A larger plant than the parent form, and less hairy.
6. Trifolium pratense perenne, sub-var. album—White Perennial Clover.—Not common, but still, like 3, an albino form, and is, perhaps, more delicate in constitution than the coloured sorts.
[7] In this, as well as the generality of forms, the smoother and larger growth indicates cultivation, manuring will sometimes make the difference.
Now, it appears to us that the descendants of the two types, Trifolium pratense and T. medium (see [Plate]) form the basis of the red or broad-leaved clover on the one hand, and the perennial or cow-grass clover on the other; whilst the market varieties have, perhaps, been modified by climate, soil, and probably hybridization with other sorts. It may, indeed, be that, after all, the plants described in [chapter XVII.] as two distinct species are only varieties, for though the common form of T. pratense grows everywhere on mixed soils, the more sandy positions, as the sandstones connected with the coal in South Wales, offer a greater abundance of the T. medium; and, from experiments conducted with seed of this latter obtained from near Swansea, Glamorgan, and sown on forest marble clay of the Cotteswolds, we certainly obtained plants differing very much from the typical form of T. medium, and assuming the usual broad-leaved clover variations.
Here, then, is opened up a curious subject for inquiry, which the history of the seed trade as it relates to clover-seed may tend in some measure to elucidate. Some few years ago T. pratense and T. medium were advertised as on sale by most seedsmen; in fact, the latter was the name by which what is now called cow-grass clover was known. Now, however, it is doubtful if any seedsman would pretend to send out the T. medium; but the label T. pratense perenne has been substituted for it.
Sinclair’s figure of “Trifolium medium, marl-clover, cow-grass,” in the “Hortus Gramineus Woburnensis,” facing page 141, is scarcely a true form of the plant, as its more or less emarginate leaflets incline to the form of T. pratense; and yet, at the time this author wrote, even this was doubtful. T. medium was difficult to obtain, as he says, “All the seeds and plants I have had for this (except that from Messrs. Gibbs & Co., which proved to be the present plant—T. medium of Sinclair) have turned out only two-year lived plants, or never exceeding three, though cultivated on various soils.” We have repeatedly written for seed, and ten years ago were always supplied with samples so labelled; but in no case did we get it. Latterly seedsmen honestly confess that they have not the seed, but can send T. pratense perenne.
Now, that this latter is merely a variety of the broad-leaved clover there can be but little doubt; still the fact that it is usually more perennial in its habit is of importance. We may easily understand why it should be so, if we consider that the common broad-leaved clover in its cultivation is so much earlier than the cow-grass form, so that this enables two cuttings of the former to be made in one season, two crops of hay being taken very commonly indeed; and as the plant gets well in flower before it is cut the first time, and seed is saved from the second crop, a more exhaustive plan for the crop itself or its future perennial powers could hardly be brought about. The cow-grass clover, however, is a fortnight and more later, which renders it difficult to cut two crops; and so its method of growth is not so exhaustive. We know that the common wild clover is said to last only two years, but with constant depasturing we see no reason why the same roots should not send up herbage for five or even ten years.
However theoretical such inquiries may be deemed, yet it must be confessed that they are of great practical importance; for, if a plant has a tendency to run into varieties, it makes it daily more difficult to get its seed true to sort; and if we are liable to have a sample, part of which may be less hardy or part more tardy in its development, it follows that much of it may never arrive at maturity, whilst if it does, as the crop will be uneven, it can never be reckoned upon for so good a yield.
Much of the variable nature of the sorts which we observe in a clover-field may be the result of the mixing of seeds from different and distant localities: if so, it is much to be regretted. But this only tends to show us how important it is that seed should be grown with care, to which end, as regards clover-seed, we sadly want some well-conducted experiments on different varieties, especially of a wild native plant, with a view to obtain a sample with good, permanent, and even qualities. In fact, the question of true of sort is altogether different from that of purity of sample; but that very serious mischief arises from the want of the latter will be discussed in another chapter.