1890.] History of Garden Vegetables. 629 
logical peculiarities of these two layers in about the same from 
the fifth to the eighth day. The middle layer consists of rounded 
cells with numerous granules; seen from the surface their di- 
ameter is greater than that of the cells outside them, but much 
less than that of the cells underlying them. While we know 
that the middle layers are ectodermal, it is uncertain whether the 
inner layer is really entodermal or really belongs with the two 
outer layers as part of the primitive blastoderm or ectoderm; 
in the latter case, the true entoderm of the archenteron must arise 
later, as we must consider probable also for the reason that the 
primitive streak is not yet formed. 
HISTORY OF GARDEN VEGETABLES. 
BY E. L. STURTEVANT. 
(Continued from p. 332.) 
ROCKET SALAD. Brassica eruca L. 
pue strong and to most persons offensive plant has been long 
under culture, and is even now highly esteemed by the 
Greeks and Turks, who prefer it to any other salad! It was cul- 
tivated by the ancient Romans. Albertus Magnus? in the thir- 
teenth century speaks of it in gardens; so also does Ruellius? in 
1536, who uses nearly the present French name, rogueta. In 
1586 Camerarius' says it is planted most abundantly in gardens. 
In 1726 Townsend’ says it is not now very common in English 
gardens, and in 1807 Miller's Dictionary? says it has been long 
rejected. It was in American gardens in 1854 or earlier,’ and 
is yet included by Vilmorin? among European vegetables. 
1 Walsh. Hort. Trans., VI., 5 
? Albertus Magnus. De Veg., Jessen Ed., 1867, 5o7. 
3 Ruellius. De Nat. Stirp., 1536, 513. 
1 Camerarius. Epit., 1586, 306. 
5 Townsend. Seedsman, 1726, 18. 
$ Miller's Dict., 1807. 
7T Brown. Pat. Off. Rept., 1854. 
8 Vilmorin. Les Pl. Pot., 1883, 541. 
