"(2) The outside part next the rind is richer in dry matter than the inner part. As we proceed from the outside toward the center the dry matter falls. This is true, no matter in what direction we proceed, but the difference from crown to center is greater than the difference found in any other direction.
"This analysis shows that a sample taken from a turnip by boring can represent only approximately the composition of the turnip. In order accurately to obtain its composition, the whole turnip would require to be used, or at any rate a wedge passing through the center from top to tail would require to be taken from it." Type distinctions.
Some of the differences between common turnips and rutabagas are brought out in the following table: During the second year both turnips and ruta bagas send up a strong stem which bears many branches. The leaves produced at this time are generally bluish green and smooth in both cases. The flowers of the rutabaga type are much like those of the cabbage, being large and creamy yel low, with long claws ; those of the turnip type are more like the flowers of the mustards, being small and sulfur-yellow, and short-clawed. Thus far, no one has found any marked distinguishing features of the seeds of these types, although it is now pos sible to detect seeds of charlock or wild mustard in a sample of turnip or cabbage seed and to distin guish between seeds of turnip and cabbage. For data on this, consult Bulletin No. 29, United States Department of Agriculture, Division of Botany.
As mentioned elsewhere (page 540), a hybrid turnip, or cross between a rutabaga and a common turnip, may have the characters of either parent blended in any number of ways.
Botanical relations.
In several of the Brassicas, selection of plants for economic purposes has been so long continued that the descendants of an original plant are now so diverse that they may be regarded as distinct species. The original plant from which the ruta baga has been derived is held by some to have been the result of a cross between the wild cabbage and the wild turnip, but such has not yet been proved. This plant (Brassica eampestris), however, has given rise to several others, among which may be mentioned the colza or rape (Brassica eampestris, var. oleifera), the best oil plant of Europe, annual
in duration and developed for its seeds (see under plants); and Brassica campeslris, var. rutabaga, DC., which is biennial in duration and has been developed for its roots for stock-feeding. The same diversification is seen in the case of the wild turnip (Brassiea Rapa). Brassica Rapa, var. oleifhra, or the thin-rooted turnip, is an annual grown for its seeds to furnish oil, while Brassica Rapa, var. de pressa is grown for its thickened root and is biennial in duration. The relationship of these plants to each other and to the hybrid-turnips is shown graph ically below : Classification of varieties.
Turnips are classified commercially according to their (1) Shape.
(2) Shape of the upper part of the root.
(3) Color of the upper part of the root.
(4) Color of the flesh.
(1) Shape. Turnips are said to be flat when the width of tuber is one and one-half times the depth ; globular when the crown and base are de pressed like a globe, but the width is less than one and one-half times the depth ; round when spheri cal in outline in all directions ; tankard when the depth is less than two and one-half and more than one and one-half times the width and the sides are parallel; ovoid when the depth is less than two and one-half and more than one and one-half times the greatest width and the sides are not parallel, but taper toward the top and bottom ; long when the length is over two and one-half times the greatest width ; half-long when the roots taper from the shoulders to the root but the length is less than two and one-half times the width ; cowhorn when the roots are twisted like a cow's horn.
(2) Shape of the upper part of the root. They may be "flat-topped" or "round-topped" according to the shape of the upper part of the root and the character of the shoulders. A concave or depressed top is objectionable, since it permits the lodgment of water and encourages diseases.
(3) Color of the upper part of the root. Roots are said to be white-, yellow-, green-, bronze-, gray-, purple-, red- or black-topped. The term "grey stones" is also applied to roots having the upper part mottled with green and purple streaks.