THE WHOKLED MILKWEED AS A POISONOUS PLANT. 
The natural habitat of Asdepias galioldes is dry plains and foot- 
hills. In the foothills of Colorado and New Mexico it seems best at 
home in the bottoms of draws. In southern Utah it occurs frequently 
in sandy, rolling plains. In New Mexico it reaches an altitude of 
about 7,500 feet and in southern Colorado 7,000 feet. 
Its downy seeds are adapted to wind dispersal, but in the irrigated 
orchards and fields, where whorlecl milkweed is becoming abundant, 
the rapid increase has been due largely to water transportation of 
seeds. The irrigating ditches have pro'ved to be ideal for the trans- 
portation, germination, and development of seeds. Wherever ditches 
have been dug in the neighborhood of whorled milkweed young plants 
have developed along the water line and spread by means of hori- 
zontal roots and seeds. The main ditches carn T seeds into the 
laterals and thence into the open fields. Fortunately the milkweed is 
a sun-loving plant and does not germinate or grow well in the shade. 
There is little evi- 
dence that it estab- 
lishes itself in fields 
with heavy cover 
crops like alfalfa, 
but a poorly seeded 
field may be just the 
place for it to get a 
strong foothold. In 
old orchards where 
the milkweed gets a 
start it runs riot, 
often forming a 
solid mat between 
the trees. 
The rapidity with which the plant spreads along the ditches is 
amazing. The orchard country at Grand Junction, Colo., has been 
ditched by various projects, the last and uppermost of which is the 
United States Reclamation Service ditch. Lateral ditches from this 
main ditch, dug in new ground but three years ago, are fringed 
with milkweed. 
In the Grand Junction region much of the stock poisoning is caused 
by milkweed in the hay. The trees in many milkweed-infested or- 
chards there have been removed and the land sown to alfalfa. 
Another orchard country, on the North Fork of Gunnison Eiver, in 
Delta' County, Colo., has no milkweed in its hay, but heavy losses 
of stock are reported at the time the animals are trailed to and from 
the summer ranges in the mountains. Ditches and fence rows along 
these trails often have quantities of milkweed which the stock eat 
when forage becomes scarce. 
Fig. i. 
-Distribution of Asdepias galioldes 
States. 
in the United 
