THE WHORLED MILKWEED AS A POISONOUS PLANT. 5 



A considerable quantity of the plant was collected and sent to the 

 Salina experiment station, where experiments, which were imme- 

 diately undertaken, proved it to be extremely toxic. 



Assistant Botanist Eggieston spent most of Jnlj, August, and 

 September, 1918, in investigating the distribution and habits of the 

 whorled milkweed in Colorado, Utah, and Xew Mexico. 



DESCRIPTION OF ASCLEPIAS GALIOIDES. 



Asclepias galioides^ whorled milkweed. The stems are erect, sin- 

 gle, or several, sometimes branching, "near woody " at base, and from 



1 to 5 feet high ; the main roots are horizontal, often branching, with 

 adventitious buds producing new stems ; the leaves are in whorls, from 



2 to 6, narrowly linear, from 2 to 4 inches long ; the flowers are in um- 

 bels from one-half to 1 inch across, at the ends of branches or in the 

 axils of leaves; the 5 greenish- white sepals are ovate, reflexed, and 

 persistent ; the petals are united ; there is a crown of cornucopialike 

 segments with horns attached between the corolla and stamens; the 

 stamens are 5 in number, and the pollen coheres in a waxy mass 

 which is removed bodily by insects ; the pods are from 1 to 3 inches 

 long, narrow, hairy, splitting on the sides ; the seeds are flat, reddish- 

 brown, with a tuft of long, silky hairs at sununit. It flowers in June 

 and July, the blooms often continuing until September. 



Plate I illustrates the mature plant, showing both flowers and fruit. 

 Plate II shows also the root, and Plate III shows the extended root 

 system of even small plants. Plate IV, figure 1, shows the plant 

 growing in an abandoned orchard. 



There seems to have been some confusion in regard to the sys- 

 tematic position of the whorled milkweed. Glover, 1917, and Glover, 

 Newsom, and Robbins, 1918, call it A. verticiUata. The plant col- 

 lected in southern Utah, as stated on page 3, was known as A. subu- 

 latd. A special study of the subject was made by Mr. Eggieston with 

 the following result : 



The whorled milkweeds were named by Dr. Gray, 1886, as follows : 



Asclepias mexicana. 



Asclepias verticiUata. 

 var. subverticillata. 

 var. pumila. 



A. galioides was first described by Humboldt, Bonpland, and 

 Kunth, 1818, from the State of Michoacan, Mexico. 



Miss Anna M. Vail, 1898, separated the group into 7 species. 



Wooton and Standley, 1915, considered A. galwides the common 

 New Mexico species of whorled milkweed and then reached the fol- 

 lowing conclusions in regard to other species : 



Our specimens may include A. verticiUata, but we have been unable to sepa- 

 rate tliem definitely. They also include specimens cited by vai'ious authors as 



