COMMERCIAL TURKESTAN ALFALFA SEED. 5 
HOW COMMERCIAL TURKESTAN ALFALFA SEED CAN BE IDENTIFIED. 
In new of the facts already set forth, it appears necessary to warn 
alfalfa growers to avoid the use of commercial Turkestan seed. Seed 
from this source has nothing to recommend it for general use in this 
country. 
Forunately, commercial Turkestan alfalfa seed can be identified 
by thepresence of the seeds of Russian knapweed (Centaurea picris), 
shown in figure 1. These seeds are believed to be always present in 
commecial Turkestan 
seed aid have not been 
found q commercial 
seed frcn other sources. 
Russian knapweed is a 
pernicios weed in the 
Crimea and in other 
parts of southern Euro- 
pean Ruda, but there is 
at the pesent time no 
alfalfa sed produced in 
these sect) ns for export. 
In manrr of growth, 
Russian aiapweed is 
similar t( quack-grass, 
Johnson <ass, and the 
Canada trtle, being a 
perennial, spreading 
both by see, and under- 
ground rootocks. The 
seeds of Rsian knap- 
weed are slhtly larger 
than those cdfalfa and 
can not all removed 
by any pjpticable 
method o machine 
cleaning. TV chalky- 
white color mes them especially conspicuous, and their symmetrical 
form, being shtly wedge shaped, serves to distinguish them from 
the notched si. f other species of Centaurea, which often occur in 
Italian and o r alfalfa seed. As the seeds of Russian knapweed 
are not usualiabundant, a small trade sample should never be 
used to determ whether the seed is commercial Turkestan alfalfa. 
It may often hoen that a number of small samples, such as are 
usually supplier the trade, would contain none of these seeds, 
while an exami^on of the bulk will show them to be present. If 
any seeds of RUm knapweed occur, the alfalfa seed is wholly or in 
part from Turke^ 
Fig. 1.— Seeds of Russian knapweed mixed with alfalfa seeds. 
('Magnified five diameters.) This sample shows a much larger 
proportion of the weed seeds (distinguished by their lighter color 
and their symmetrical form) than is ordinarily found in 
Turkestan alfalfa seed. 
