ON BRASSICA POLYMOKPHA. 195
subspontaneously as the remains of cultivation; and, probably, often figure in herbaria and local lists as B. campestris.
B. Riipn, De Cand., the Turnip in its esculent rooted state, falls into two I'aces, which have always been distinguished in books, — the varieties depressa and ohlonga of De Candolle, Besides these, a slender-rooted form, cultivated as an oil plant in Dauphiny, was ascertained by experi- ment, in the Geneva Botanic Garden, to belong to this species, and must, therefore, be the same as the Thames-side Brassica.
B. Napus, De Cand., is probably almost unknown in this country. I have examined fields of llape in Gloucestershire, and have always found the young leaves to be hispid. 1 conclude, therefore, that this could not be Napiis. In Forster's Herbarium in the British Museum there is a young plant of, I presume, this species, as the leaves, as far as I could see, are quite glabrous. This is the only example I have come across. Mr. Watson speaks of Rape Avith the synonym Napus in his paper (viii. 271). If this is correct, which I do not think it to be, B. Napus ought to occur as a waif of cultivation, at any rate, in sheep-farming dis- tricts. In the ' Cybele ' (i. IfiO), however, he says, " I have never seen — at least, never recognized — the species." It is apparently cultivated on the Continent both as an oil- and root-yielding plant. Its root, called " navet," is often coufouiuled with the Tankard Turni)i, but seems to have been generally pretty clearly distinguished (Cf. R'lpum obloiifjius and Napus, Dod. Pempt. 673, 674). It is a common vegetable in Continen- tal gardens, though apparently hardly, if ever, cultivated in England.
If we turn to the diagnoses of these plants given by LiiuicTus, while there is no difficulty in determining what is meant by his B. Rapa and B. Napus, the identity of his B. campestris is very uncertain; in fact, all that can be certainly stated of it is, that it was a troublesome weed in parts of Sweden. The description merely states that it had a slender root and uniform cordate sessile leaves. The synonyms given in the ' Hortus Cliftbrtianus ' (p. 339), to which reference is made, apparently belong to either Erysmiim or'ieidale, Br., or E. auslriacum, Jacq.; and Lamarck has united the former species {■^= Brassica orieutulis, L ) with B. campestris, L., which he considers the same as E. austriacitm, Jacq., under the name of B. perfoliata (Kncyc. Method.).* Mr. Watson believes B. campestris to be the wild and slender-rooted tbrm of B. Rapa, the same, in fact, as the Dauphiny plant of De Candolle; and he remarks that Grenier and Godron follow Lamarck in using the expressive name asperifoUa for the aggregate species, making campestris, L., its type-form, and Rapa, L., the esculent-rooted variety. But Lamarck, in the ' Encv- clopedie Methodique ' rather unintelligibly joins not campestris, but Napus to Rapa, notwithstanding that Linna3us states Napus to have glabrous leaves. Koch also (Syn. Fl. Germ, ed. 2. i. 59) considers B. campestris, L., to be an annual variety of B. Rapa, and the same as B. prcecox. Kit.; which is puzzling, as De Candolle describes that plant as having all glal)rous glaucescent leaves.
It is, of course, quite obvious that if Linnaeus's cainpestris M-as' a
- In the Herbarium (now in the British Museum) of Linna3us, containing the
originals of the ' Hortus ClilFortianus,' Bransica campestris pcrfotiata, Jlorc albo, B. P., is B. orientalis, L. [ — Eri/simHm orientale, R. Br.), and B. camptstris per- foliata, fl. purpureo, B. P., is li. anr/isis, Ij. {=Moricaiulia arveiisis, I3o Cand.); neither of these are Scandinavian plants. {II. T.)
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