182 M. De CandoUe on the Species and Varieties 



tivated for the oil contained in its seed, and appears to be the 

 most productive of any that are used for tlie same purpose. 

 But such is the confusion existing in the nomenclatine of these 

 plants, that it is difficult to know, without the minutest de- 

 scription, wliich are to be referred to the same species. The 

 one now under consideration appears to be the true Colsa, 

 cultivated in Belgium, and in several of the eastern parts of 

 France, in Germany, and in Switzerland : in other provinces 

 the name of Colsa is given to the Brassica Naj)iis oleij'era, or 

 Navette iV hiver, while the Brassica campestris oleifera is simply 

 called Navette. So we mvist refer the Colsa of Duchesne 

 and Lamarck to the Brassica Napus, as well as the plant de- 

 scribed in the Flora Britannica * under the name of Coleseed : 

 on the other hand, in the greatest part of the Netherlands, and 

 France, Colsa implies the Brassica campestris oleifera, so that, 

 to prevent any mistake, I have chosen oleifera for the me- 

 thodical nomenclature, which is at least as comprehensible as 

 the names of Colsa and Coleseed, both merely signifying Cab- 

 bage seed, in the German origin. It would be desirable for 

 agriculture that in all countries, cultivators would examine 

 whether the plant they rear is the Brassica camp)estris oleifera, 

 or the B)assica Nanus ale f era, which can easily be ascertained 

 by observing v/hether the young j)lant is rough or smooth ; if 

 hispid, it is the Brassica campestris ; if glabrous, the Brassica 

 Napus. Experimentsf made by M. Gaujac show the produce 

 of the first, compared to that of the second, as 955 to 700. 

 The true Colsa, the plant now described, is generally sown 

 about the middle of June, in well manured nursery ground, 

 from whence it is transplanted after harvest into fields properly 

 prepared, and manured again in November, after which, it 

 stands the winter tolerably well, blossoms in the spring, and 

 soon after runs to seed. 



There is a variety of Colsa, called in France Colsa dc Mars, 

 which may be sown in spring, and harvested in the same year. 

 It is less productive, but may be employed on ground that has 

 not been prepared soon enough in the preceding year, or to 

 replace those plants of other kinds that have jierished in win- 

 ter. I have seen both these varieties, when sown in the same 

 ground in the month of May, wear a very different aspect in 

 September: the early or spring one,j)ra;cox, was in full blossom, 

 and the late or autumn one, antumnalis, had not the slightest 

 appearance of a flower. Some authors speak of a variety 

 called the white-flowered Colsa, but as I have constantly seen 



* See Brassica Xapii.t in Smith's F/oin Britannica, vol. ii. page 719, 

 and English Botany, plate 2146. f See tlie end of this Memoir. 



the 



