188 REPORT OF THE DEPARTMENT OF BOTANY OF THE 
arvense (L.) Scop.), chicory (Cichorium tmtybus L.), charlock 
(Brassica arvensis (L.) Ktze.), black mustard (Brassica nigra 
(L.) Koch.) and quack grass (Agropyron repens (L.) Beauv.). 
The question naturally arises, how great is the risk incurred in 
sowing impure alfalfa seed and what are the most dangerous im- 
purities? .As stated above, the risk on dodder is certainly large. 
The damage done by this pest is discussed more fully on page 197. 
Narrow-leaved plantain and wild carrot are troublesome weeds, but 
the great majority of New York farms are already infested with 
them so that the sowing of a few additional seeds with alfalfa seed 
can do no great harm. However, there are some careful farmers 
who are making strenuous efforts to keep their farms free from 
these weeds. To such persons, even a small amount of narrow- 
leaved plantain or wild carrot in alfalfa seed would be objection- 
able. Canada thistle, curled dock, mustard and charlock are all 
very bad weeds and few persons would care to use any seed contain- 
ing them. Fortunately, they do not occur in alfalfa seed very fre- 
quently ; besides, it is probable that all of them find much difficulty 
in establishing themselves in alfalfa fields. Further discussion of 
this subject will be found on page 214. 
The danger from weeds is often greatly overestimated. The 
Russian thistle 1s a conspicuous example. About fifteen years ago 
much ado was made over the Russian thistle and several of the 
experiment stations published sensational bulletins on the subject. 
Subsequent events have shown the weed to be quite unimportant.” 
Certainly, New York farmers have nothing to fear from it. Al- 
though seeds of Russian thistle must have been sown with alfalfa 
seed many times the plant is almost unknown here. There have 
come to our attention only two instances in which Russian thistle 
has appeared in alfalfa fields in New York. Both of these occurred 
in 1908 — one near Geneva and the other at Halls Corners. We 
have not seen it growing elsewhere in the State. However, Peck*® 
records its occurrence near Rochester and Prof. W. W. Rowlee of 
Cornell University informs us that it is quite abundant around the 
salt sheds and on the waste of the Solvay Process Co., at Syracuse. 
ADULTERATION. 
Alfalfa seed is sometimes adulterated. Each year, during June, 
the Station receives almost every day one or more specimens of a 
* Bessey (5). 
” Peck (75). 
