10 
Bulletin 113. 
Poisonous Plants. 
larkspur. ( Delphinium .) 
There can be no question but that the several species of larks¬ 
pur growing native in the mountainous districts of Colorado are 
a greater source of loss to the stockmen than all other weeds 
combined. While the larkspur is confined to the mountainous 
regions, it nevertheless holds true that in the aggregate mortality 
throughout the State from poisonous plants larkspur takes second 
place only to loco. We have no statistics at hand whereby we can 
estimate, with any degree of accuracy, the total loss, but judging 
from the reports of other western states and from information re¬ 
ceived from most every section of the State, it would seem that 
$40,000 annually is a conservative estimate. 
There are four species of larkspur found growing abund¬ 
antly in the middle and western portion of this State, and one 
found growing sparingly in the eastern plains section. Other species 
have been found in isolated places, but have not been especially 
accused of doing any harm, and their toxicity has not been proved. 
The four species found in the greatest abundance and named in 
the order of their importance, are purple larkspur, Delphinium 
Nelsonii, Greene; tall larkspur, Delphinium elongatum, (Rydb.) ; 
D. Geyeri, (Greene), and D. Barbeyi, (Huth). These all 
have the same characteristic flowers, and are found growing in the 
mountains at altitudes from 5,000 to 11,000 feet. The D. Penardii 
(Huth), has a white flower and may be seen growing adjacent to 
streams and in the arroyas on the plains as far east as the State 
line. 
In June last this letter of inquiry was addressed to one thous¬ 
and stockmen in the State, and a fairly liberal response was re¬ 
ceived. 
Dear Sir: 
The Experiment Station is conducting an investigation in connection 
with the U. S. Department of Agriculture, on the range plants of the 
State, poisonous to stock, and desires the benefit of your experience and 
observations on the subject. The information obtained will be collated 
and published and copies will be sent to all who have assisted with informa¬ 
tion and experience. 
The Experiment Station will more particularly take up the question 
of larkspur and poison plants other than loco. 
Please answer as many of the questions as you can, and forward the 
