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.
[7] In this, as well as the generality of forms, the smoother and larger
growth indicates cultivation, manuring will sometimes make the
difference.
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.
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.
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.