The sort known in the market as _T. pratense perenne_ is probably intermediate between the wild species _T. pratense_ and _T. medium_. Our own experiments have shown that, on cultivating _T. medium_, which is a sand-lover, in strong land, in three years it has been very difficult to distinguish it from some of the varieties of _T. pratense_. We incline, therefore, to the opinion that as the _T. medium_ holds to sandy soils in the wild state, its seed was brought into cultivation with a view to light-soil cropping; and from this source has probably been derived the so-called _T. pratense perenne_, which variety is certainly more perennial in such light soils as would be quite unfit for the true _T. pratense_. The latter, indeed, seems to be more permanent in soils containing a quantity of lime, while the former, where it can be got of a good sort, is certainly best adapted for sandy soils. 2. _Trifolium medium_—Zigzag Trefoil—is distinguished from the _T. pratense_ by its larger, but more lax, head of reddish pink (not purple) flowers, which are solitary, on the apex of a stalk, which at each joint is bent at a considerable angle; hence its name. Its leaflets are elliptical, and not broader at the upper margin. This plant is a constant denizen of sands and light soils. In fact, its naturally growing in soils unfitted for the broad-leaved clover seems to recommend it for cultivation; and though, as before pointed out, we more than suspect that the so-called cow-grass clover was originally derived from this source, and that the _T. medium_ is after all but a variety of the _T. pratense_, it is now quite merged as a farm-plant into the broad-clover forms; so that, if we are to possess it as a separate plant, it must be again grown from the wild seed; and then, if it is to be kept pure, it must not be cultivated on clays or limestones, or, if our view be correct, it will soon lose its true distinctive character.