IG 
CoLouADO Experiment Station 
Pig-. 12 — Map of Colorado giving- present known distribution of whorled milk- 
weed. 
Pig. 13 — In new regions the milkweed occurs in patches 
on the ditchbanks. 
7,000 feet. The altitudinal range of best growth in this State is 
from about 5,000 feet to 6,500 feet. 
The plant is commonly found along ditch banks, roadways, 
and railroad right-of-ways, in fence rows (Fig. 14), and 
