1907] Another Locality for Eruca Sativa. 161 



ANOTHER LOCALITY FOR ERUCA SATIVA. 



To Mr. Macoun's report in the October issue of The 

 Ottawa Naturalist, of the discovery of the European plant 

 Eruca sativa, in two widely separated parts of Canada, I am 

 able to add another distinct locality; namely, Preston, Waterloo 

 County, Ontario. The plant was found in flower about the first 

 of August, in a small field of lucerne, which had been sown in 

 June. It was present in considerable quantity, and had been 

 passed over as ordinary mustard {Brassica Sinapistrum) , until 

 one day when I went into the field and saw it at close quarters. 

 The habit of growth, size and superficial resemblance of leaves 

 and flowers contribute to this similarit}^ to mvistard. A glance 

 was sufficient, however, to show that it was something new. 

 On endeavoring to determine the species of the plant, I found 

 m3'self beaten ; and all our efliorts to trace it out in both Ameri- 

 can and English botanies proved futile. On October 31st I 

 took advantage of an opportunity to show my specimens to 

 Dr. Fletcher, Ottawa, who having just read the aforementioned 

 report, and also having seen the plant in Europe manv years 

 ago, identified it as Eruca. 



There are several characters by which this plant can be 

 quite readilv distinguished from wild mustard. The leaves are 

 always more or less deeply lobed pinnately. The flowers are 

 not quite so brightly colored, and the petals are distinctly 

 veined with purple. When the plant has developed pods, it 

 can be known with certainty by these. The whole upper third 

 of the pod is a flat empty beak. 



A noteworthy peculiarity about the plants which I have 

 seen is their extreme variabiht}^ apart altogether from the 

 influence upon them of crowding by other plants, Or of any of 

 the conditions of growth, so far as I have been able to observe. 

 This is shown most strikingly in the leaves and pods. In some 

 specimens the leaves are only very slightly lobed, while in others 

 they are cut in almost to the midrib. The pods vary in .shape, 

 those on some plants being shorter and plumper than on others. 

 Some pods, too, are nearly smooth, while those on other plants 

 have a dense pubescence. 



I have not as yet been able to learn an^-thing definitely 

 about the source of the seed with which this weed was introduced. 

 It seems probable that the infestations so far known about, 

 may have entered the country together, since the medium in 

 each case is the same; and that there may be therefore many 

 more to be heard from when the weed becomes known. 







H. Groh. 



