Hence, then, it is concluded that such plants as are grown for their roots have a peculiar aptitude for laying on tissue, and thus increasing the bulk of their “descending axis,” that is, that portion of their structure which grows downwards—root. Besides this, they are remarkable for their capability of producing varieties—a fact which, united with a constancy in the maintenance of an induced form, renders it exceedingly easy to bring out new sorts which will maintain their characteristics under great diversities of climate, soil, and treatment.
The facility with which different sorts of roots may be procured can readily be understood from the many varieties, not only of turnip—which may perhaps be considered as an original species—but also of swede, which is a hybrid of the turnip and rape plant. Of the former we have more than thirty sorts grown by the farmer, and as many peculiar to the garden; whilst there are probably more than twenty well-recognized sorts of swedes. Of beets, with mangel-wurzel, we have almost as great a variety; so also of carrots. Of parsnips we have fewer varieties, to which may now be added the new form called the Student parsnip, the growth of which is so interesting that we shall here give a short history of its production, as an illustration of the origin of root crops.
Figures 1 and 2.—Roots of Wild Parsnips. Natural size.
In 1847 we collected some wild parsnip seed from the top of the Cotteswolds, where this is among the most frequent of weeds. This seed, after having been kept carefully during the winter, was sown in a prepared bed, in the spring of 1848, in drills about eighteen inches apart. As the plants grew they were duly thinned out, leaving for the crop, as far as it could be done, the specimens that had leaves with the broadest divisions, lightest colour, and fewest hairs. As cultivated parsnips offer a curious contrast with the wild specimens in these respects, we place the following notes, side by side, on the root-leaves of plants of the same period of growth.
| 1st. Wild Parsnip. | 2nd. Student Parsnip. | ||||||
| Ft. | in. | Ft. | in. | ||||
| Whole length from the base of the petiole to the apex of the leaf | 0 | 8 | Whole length from the base of the petiole to the tip of the leaf | 2 | 0 | ||
| Breadth of leaflets | 0 | 0 | 3⁄4 | Breadth of leaflets | 3 | 0 | 1⁄4 |
| Length of ditto | 0 | 1 | Length of leaflets | 0 | 6 | 1⁄2 | |
| Petiole and leaflets, hairy. Colour, dark green. | Petiole and leaflets without hair. Colour, light green. | ||||||
We have before remarked that neither in size nor form are the wild roots at all comparable with the cultivated ones. Our [figures] 1 and 2 were taken from fine roots of the wild parsnip of the first year’s growth; that is to say, just at the same time as a crop parsnip would be at its best. They were purposely taken from specimens obtained from the same district as the seed with which our experiments were commenced.
Our first crop of roots from the wild seed presented great diversities in shape, being for the most part even more forked than the originals, but still with a general tendency to fleshiness. Of these the best shaped were reserved for seeding; and having been kept the greater part of the winter in sand, some six of the best were planted in another plot for seed. The seed, then, of 1849 was sown in the spring of 1850, in a freshly-prepared bed, the plants being treated as before, the results showing a decided improvement, with tendencies in some examples in the following directions:—
1st. The round-topped long-root, having a resemblance to the Guernsey parsnip. (Panais long of the French.)
2nd. The hollow-crowned long-root. “Hollow-headed” of the gardener. (Panais Lisbonais type.)
3rd. The short, thick turnip-shaped root. “Turnip-rooted” of the gardener. (Panais rond form.)