[10] Some examples of this plant, gathered at Framilode, in the Vale of Gloucester, in the past autumn, gave as many as 750 seeds to a root, from which its rate of increase as a weed may be imagined. 2nd. _Avena fatua_, var. _sativa_, with loose panicles of flowers, florets quite smooth, tumid, with or without straight awns, some few examples slightly hairy towards the base. This is the potato-oat type. Six parts of crop. 3rd. _Avena fatua_, var. _sativa_—Panicles more compact, flowers inclining to one side, grains more tumid than 2nd, quite devoid of hairs, awn straight. These present the type of the white Tartarian oat. Twelve parts of crop. Fig. 2. See plate. Having now procured a crop of separate types of oat from the same seed, we preserved them distinct, and this year carried on our experiments by cultivating a patch of each, whilst the plot of 1856 was left with self-sown seeds, in order that it should again become wild by degeneracy. From these experiments, then, we may conclude that different types of crop oats are derived from the _Avena fatua_, or wild oat; but, besides this, they open out a subject for inquiry of great practical interest and importance, which may be clearly stated as follows:— If by cultivation the wild oat assumes the cultivated form, then by degeneracy cultivated oats may become wild ones. Those who know what a detestable weed is the wild oat wherever it occurs, and how difficult it is to eradicate,[11] will at once see the cogency of the question involved. [11] The author once went with a rector of a parish in Gloucestershire to examine the glebe allotments of the poor people, when, catching sight of an apparent crop of oats, the landlord threatened to dispossess the tenant, “because he had carelessly left his crop without gathering.” However, the matter was explained when it was pointed out that the land was planted with wheat, which the oats had quite smothered. Farmers in some districts, and more especially on stiff clay soils, have ever objected to the cultivation of oats, as they had always maintained that they left behind a crop of weed oats. This, which was never a favourite idea with the botanist, who is generally too much inclined to species-making, seems now to have a basis of truth, for not only is it confirmed by the experiments described, but observation of an independent kind points to the same truth. On examining the produce of shed, or accidentally scattered oat seeds, the first crop will often present the wild tendency in a partial reversion to the hairy state, an elongation and thickening of the awn, and a lessening of the size of the kernel; and this more particularly on heavy soils. It was, indeed, an observation of this change in oats scattered on forest marble clay which induced us to try the experiments above detailed; and as the subsoil of our botanical garden is the same clay, we are, perhaps, indebted to this cause for arriving so soon at such signal results.