Oct. is, 1930 Mustard Seeds and Substitutes: I. Chinese Colza 121 



He thus takes a different stand from all other botanists who have given 

 attention to these "Chinese cabbages and mustards." The authors of 

 this paper also disagree with Bailey 's viewpoint and classification on the 

 basis of a rather extended investigation reported in the following para- 

 graphs. There is no doubt in their minds that the so-called Chinese 

 cabbages are not mustards but belong to the colza group, Brassica cam- 

 pestris L. 



Concerning Brassica campestris L., Prain (52) states: 



From the standpoint of commerce it is a matter of supreme indifference whether 

 campestris, napus, and rapa be treated as separate species or subspecies of one and the 

 same species. 



Consequently, in his systematic synopsis he proposes a number of 

 groups : 



(1) Brassica oleracea, cabbage group; and (2) Brassica campestris Linn. ampl. Sub- 

 species A, campestris (sp. Linn.), representing the colza group, subspecies B, napus 

 (sp. L.) representing the rape group, and subspecies C, rapa (sp. L.) representing the 

 turnip group. 



As to the close relationship of the respective forms, Bailey states (j, 

 p. 544) that he — 

 ound no difficulty in crossing cabbage-kale-cauliflower and others. 



Lund and Kiaerskou, especially, showed by extensive crossing experi- 

 ments the close relationship of Brassica oleracea, Brassica campestris, 

 and Brassica napus. Notwithstanding this close relationship, however, 

 it appears necessary to go further than Lund and Kiaerskou (28) in the 

 classification of some of these forms, for instance in the classification of 

 Pak-choi and Pe-tsai. Bailey states (2, p. 180) — 



there is even good reason for separating the two types of Chinese cabbage . . . 

 into two species, for they differ widely in their leaf characters and pods; and the former 

 [Brassica pe-tsai] is truly annual, while the latter [Brassica chinensis] is evidently 

 normally biennial. 



Although the authors did not study these forms extensively, Shoemaker 

 has shown that they can be readily crossed (PI. 15, B) and therefore 

 should not be considered as having species character (4). It is at pres- 

 ent impossible to state definitely the relationship of Chinese colza to 

 these forms. Since it has greater similarity to Pak-choi than to Pe-tsai, 

 it appears not unlikely that Chinese colza and Pak-choi have developed 

 from one common stock. Pe-tsai may present a further modification 

 of Pak-choi, since, it is said, plants with narrower petioles may develop 

 from Pe-tsai seeds. Pending further collection of data on Pe-tsai and 

 Pak-choi the following classification, based on that of Bailey, Lund and 

 Kiaerskou, Gagnepain, and others, appears satisfactory for the separa- 

 tion and identification of these horicultural and oil-yielding forms : 



1. Pak-choi, Brassica campestris chinensis T. Ito. 



2. Pe-tsai, Brassica campestris pekinensis (Lour.) Viehoever. 



3. Chinese colza, Brassica campestris chinoleifera Viehoever. 



