10 



BULLETIN 942, U. S. DEPARTMENT OF AGRICULTURE. 



EXPERIMENTAL WORK WITH A. VERTICILLATA VAR. GEYERI. 



A. verticillata, the whorlecl milkweed of the eastern part of the 

 United States, is distributed throughout the Atlantic Plains and the 

 Mississippi Valley. It differs materially from A. galioides, A. 

 pumila, and A. mexicana in that it has long, fibrous roots and smooth 

 pods. 



A. verticillata var. geyeri can be distinguished from the typical 

 form by its numerous adventitious buds on the fibrous roots. These 

 slender, fibrous budded roots are often long and horizontal and thus 

 simulate the single strong horizontal roots of A. galioides, A. pumila, 

 and A. mexicana. 



The material used in these experiments was collected at Missouri 

 Valley, Iowa, on June 29, 1919. 



Thirteen feedings of this plant were made to sheep by the balling 

 gun, resulting in two animals becoming sick and one other very sick. 

 Three feedings with hay were made to a horse, with no result. 



The following table summarizes the experiments : 



Table 5. — Summary of feeding experiments with Asclepias verticillata var. 

 geyeri (collected at Missouri Valley, Iowa, and air dried). 



Animal. 



Date of 

 feeding. 



Method of 

 feeding. 



Part of plant used. 



Weight 



of plant 

 (esti- 

 mated 



as green 

 plant) 

 for 100 



pounds 

 of ani- 

 mal. 



Remedy 

 used. 





Designa- 

 tion. 



Weight. 



Result. 



Sheep 523 . . 

 Sheep 526 . . 



Pounds. 



82 



90.5 



82 



95.5 



98.5 

 103 



97 



114.5 

 106 



89.25 



97 



129 

 92 

 995 

 995 

 995 



1919. 

 July 14 

 July 15 

 July 16 

 July 17 

 July 18 

 July 19 

 July 20 

 July 21 

 Aug. 12 

 Aug. 22 

 Sept. 20 



Sept. 23 

 Sept. 25 



July 15-16 

 July 17 



July 18-21 



Balling gun... 



do 



Pounds. 



0.140 



.184 



.276 



.368 



.735 



1.102 



1.470 



2.205 



2.021 



2.113 



2.168 



1.286 



1.470 



.072 



.15 



.133 



None 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



do... 



Not sick. 

 Do. 



Sheep 527 . . 



do 



do 



Do. 



Sheep 544 . . 

 Sheep 556 . . 

 Sheep 548 . . 



do 



do 



do 



do 



do 



do 



Do. 

 Do. 

 Do. 



Sheep 540 . . 



do 



do 



Do. 



Sheep 473 . . 

 Sheep 556 . . 

 Sheep 546 . . 

 Sheep 552 . . 



Sheep 482 . . 



do 



do 



do 



do 



do 



do 



Fed with hay . 

 do 



do 



do 



do 



Leaves and stems with 

 large proportion of 

 stems. 



Very sick.. 

 Not sick. 



Do. 



Do. 



Sick. 



Sheep 523 . . 



do 



Do. 



Horse 126 . . 

 Horse 126 . . 



Leaves and stems 



do 



Not sick. 

 Do. 



Horso 126 . . 



do.... 



...do 



Do. 











TYPICAL CASE OF SHEEP 473. 



Sheep 473 was a wether weighing 114.5 pounds at the time of 

 the experiment. On July 21, 1919, between 4.05 and 4.37 p. m., it 

 received by the balling gun, per 100 pounds of animal, 2.205 pounds 

 of the plant, estimated as green plant. At 6.40 a. m., July 22, the 

 pulse was 152, weak, but regular, and the respiration was deep. It 

 seemed weak in the hind legs and staggered as it walked. 



