Our cauliflower, about the end of the same century, was first brought from the Levant to Italy; and in the end of the seventeenth was transplanted thence to Germany. For a long time the seeds were procured annually from Cyprus, Candia, and Constantinople, by the Venetians and Genoese, who sent them to every part of Europe, because at that time the art of raising seed was not understood[860]. Prosper Alpinus, in the year 1588, found abundance of this vegetable in Egypt, and from his account there is reason to conjecture that it was then very little known in Europe. Conrad Gesner seems not to have been acquainted with it; at any rate it is not mentioned by him in a list of the cabbage kind of plants[861]. Even in the time of Bauhin it must have belonged to those vegetables which were scarce; because he has been so particular in naming the garden in which he saw it. Von Hohberg, who wrote about 1682, says that cauliflower, a few years before, had been brought to Germany for the first time[862].
It would be difficult to define all the species of the cabbage kind, the leaves and flowers of which were used by the ancients as food; but it would be a task still more arduous to determine those which have esculent roots. To render this clear, and to show what information I have been able to obtain on the subject by my researches, I must venture to indulge in a little botanical criticism. Our plant-connoisseurs have unfortunately not yet condescended to examine the class of kitchen vegetables; though it would certainly be rendering a far greater service to botany, and promote its utility much more, to describe and delineate all the species, varieties, and deviations, than to give new names to a dozen of new genera from Polynesia. According to the Linnæan system, we have at present the following species of the cabbage, which have been adopted by all botanists, without further observation.
First, Brassica oleracea, to which belong all those kinds the leaves and flowers of which are eaten. It is certainly probable that all these have been gradually produced from one parent stock, which it is now impossible perhaps to find in its original wild state. A similarity is remarked between all these kinds; and with a little ingenuity one might form a genealogical tree of them, as Buffon has done in regard to the race of dogs; but a genealogical tree without proofs is of as little value in natural history as in claims for hereditary titles or estates. At present, in our system, we must admit that such plants as always grow up from their seeds, without variation, and do not pass into other forms, are peculiar species; but this will not prove that these supposed species were not originally produced from one maternal stem; for the variation of the succeeding plants took place gradually; and the later ones always deviated more and more from the parent stock. Who knows how many steps and gradations were necessary before cabbage, savoys, and cauliflower were produced from our common colewort? Not fewer, perhaps, than were required to produce white men from Moors, or the terrier and lap-dog from the bull-dog.
I shall call the mother plant, or original species, A, which by unknown causes has produced B, and the latter by continued and frequently changed culture has become C; from this has been produced D, and from this E, and from this F, &c. Now as we are unacquainted with the art of changing A into F, and F into A, we believe that F is a species really different from A. As we here compare two distant links of a chain, the various parts of which increase very gradually, we find them so different, that it is impossible for us to consider them as the same. But sometimes, perhaps, F changes again into E; E into D; D into C; and C into B or into A. Perhaps also B may be again produced from A, or F from E. Had a botanist observed this by experience, he probably would have no hesitation to consider B, C, D, E, and F as varieties of A. But such observations seldom occur; we have not the power of making them according to our pleasure, for we do not know all the causes by which these numerous variations are produced. The few observations which have been made no one has yet collected, compared, and employed for establishing any certain conclusions. The division, therefore, of the cultivated plants into species and varieties would be a fruitless and uncertain undertaking, respecting which one ought not to dispute without sufficient proofs.
It is needless to refer to the form, colour, smell, and taste of the leaves, flowers, and roots. That the indented leaves, such as those which all the cabbage species have, are most liable to change, is shown by experience. The colour is no less variable; and Reichard, who had a great belief in the perpetuity of the species of plants, asserts, that in the same country and climate he could produce from the seeds of red cabbage and black radishes, white cabbage and white radishes[863]. The production and change of the hermaphrodite plants is so well known that it is only necessary to mention them. The smell, for example; but the musky smell of cabbage establishes no essential difference. Nay, a plant may entirely lose its odorous principle, spiritus rector, and yet retain its old form, as well as all its other component parts and properties[864]. In sandy soil the smell of plants is often entirely lost; and the taste is frequently changed, according to the nature of the land and the manure. The most powerful medicinal plants are those which grow wild in their native country, and not those reared in rich gardens, where many poisonous plants become eatable. Even the duration does not always determine the difference of the species. Thus it is certain that winter and summer rape are the same plants, though the former is a biennial and the latter an annual. Where then are the proofs in regard to the cabbage kind, and, in general, those which show that different plants are species of one genus, and others only varieties? Precision or certainty in systems can be expected only by novices; but in botany the case is the same as in every other science, mathematics excepted; the more we learn, the more uncertainty we discover, and the more circumscribed is the real knowledge which we acquire. It is necessary that this should be known to those who may take the trouble to examine the history of kitchen vegetables and other œconomical plants; and therefore I shall offer no apology for having entered into this botanical disquisition.
To the Brassica oleracea belong two plants which are used in the same manner as turnips or roots. The first is the turnip-cabbage, kohlrabi above the earth (Brassica gongylodes), the stem of which swells out, above the earth, into a thick pulpy turnip-like tubercle, which is dressed and eaten in the same manner as turnips. It is a monstrous excrescence of the stem, which is hereditary, like the broad stem of the Italian fennel. This turnip-cabbage was certainly not known to the ancients; it occurs for the first time among the botanists of the sixteenth century. Spielmann conjectures that it was brought from the Levant during the crusades; but it was known at too late a period to warrant this opinion.
Still newer is that variety called kohlrabi, subterranean or turnip-rooted cabbage, the stem of which produces a similar tubercle at the surface of the earth or immediately under it. In my opinion, it was first described by Caspar Bauhin, in the year 1620, under the name napo-brassica, which it still retains, as a new species, to which he was not able to assign any synonyms. He says that this turnip was cultivated on the Bohemian frontiers, where it was called Dorsen or Dorschen; and the same name is given to it there at present, as is confirmed by Mehler, in whose work there is a good figure of it[865]. In Germany it is commonly called Steckrübe, and, as is said, was first made known there about the year 1764 by the Bohemian glass-dealers.
The second cabbage species in the Linnæan system is the Brassica napus, a plant which grows wild on the sandy sea-coasts of England, as well as in the island of Gothland, and which in many of the northern countries is cultivated for the oil obtained from the seeds, under the name of winter and summer rape. When thinly planted in a nourishing soil it produces esculent roots, which have a somewhat harsh taste, and properly in German it ought to be called Steckrübe. Such is the name given to it in the works of all the old writers by whom it was first mentioned; and it is called so at present in Bohemia, where it is cultivated, as well as kohlrabi under the earth, which in some parts of Germany is improperly named Steckrübe, and a proper distinction is made between the two species[866]. This kind, the real Steckrübe, is never very thick, being only of the size of those which grow in the Mark. The leaves arise immediately from the roots, but in the gongylodes and napo-brassica they proceed from the stem.
This species of turnip I did not expect to find among the ancients. I conceived that it might perhaps have been produced in the northern countries, since rape began to be cultivated for oil. Afterwards this plant may have become so much domesticated among us, as to be found not unfrequently in a wild state. Some person may then have easily remarked the pulpy roots of plants growing in a manured soil, and making a trial of them found them well-tasted. When first cultivated, it must have been observed that their harsh taste was moderated, sometimes more and sometimes less, in a sandy soil, and rendered in some degree aromatic; by which means they acquired so great a superiority to the common and almost insipid rape, that they were brought to the first-rate tables under the name of the Markish, Teltow, Borsfeld, Bobenhäuser and Wilhelmsburg rapes. In each country they were named after those places where they acquired the best savour; and this was the case only where the soil consisted of clay mixed with more or less sand. From such districts large quantities of them were sent to a great distance; but perhaps never in more abundance than from Teltow, in the Middle Mark, which small town sold to the amount of more than two thousand dollars, chiefly to Berlin and Hamburg; and from Hamburg these agreeable roots were frequently sent to both the Indies. Around Stendal also, in the Old Mark, they were raised in considerable quantity, but the seeds are procured there from Teltow[867]. If we wish to introduce them into our gardens, we must either mix much sand with the soil, or procure fresh seeds annually.
The Greeks and the Romans had little occasion for cultivating rape. They had other vegetables, from the seeds or fruit of which they could obtain a better oil, and in more abundance. Where the olive would not thrive, they cultivated, as at present, sesamum; or expressed oil from the nuts and seeds of the turpentine tree[868], without speaking of the many essential oils which they used for salves.