14 BULLETTlSr 365, V. S. DEPAETMEXT OF AGEICTJLTT^EE. 



recognized as different plants. The flowers of larkspur and aconite 

 are so different, however, that few fail to recognize the difference 

 after flowering. 



SPECIES OF DELPHINIUM CONCERNED IN LARKSPUR POISONING. 



• The classification of the species of Delphinium is in a somewhat 

 unsatisfactory condition, and mitil a thorough revision of this genus 

 has been made it is hardly possible to speak authoritatively in. re- 

 gard to the distribution of the various species. Generallj^ speaking, 

 we find two great groups, the tall and the low larkspurs. The tall 

 larkspurs embrace the species that are more or less closely related to 

 the old species Delphinium, scopidorum Gray. The form that has 

 been used in the experimental work in Colorado is known provi- 

 sionally as Delphinium harheyi Huth, and gi'ows at an elevation of 

 8,000 feet and higher. Delphinium roljustum Rydb., with which a 

 single feeding experiment was carried on, is also a tall larkspur. 

 The tall larkspur used in the feeding experiment at the Greycliff 

 station was Delphinium cuculloiumv A. Xels., which is common in 

 the mountains of Montana. The species of low larkspur used at 

 the Mount Carbon station was Delphinium menziesii D. C, of which 

 the name Delphinium nelsonii Greene, is a synonym, while that fed 

 in Montana was Delphinium hicolor Xutt. The tall larkspurs grow 

 throughout the season, maturing in the late summer while the low 

 larkspurs mature and die early in July. Although experimental 

 work has not been carried on by the authors in any other States than 

 Colorado and Montana, there is every reason to think that the plants 

 found in. other localities have the same properties and produce the 

 same effects as the larkspurs of Colorado. 



From the fact that the low larkspur dies early in July, cases of 

 poisoning from this plant occur mainly in the month of June, and it 

 is commonly thought by the stockmen that the plant ceases to be 

 poisonous when it blossoms; but as shown elsewhere in this report, 

 it is probable that it is poisonous during its whole life. The fact 

 that fewer cases of poisoning occur when the plant is in flower is 

 probably because at that time nutrient grasses are more abundant 

 and the animals eat less of the larkspur. The tall larkspurs are also 

 poisonous early in the season and these poisonous properties, as 

 shown elsewhere, may continue until the maturity of the plant. 

 The cases of poisoning which occur in other States are due to species 

 which correspond in general with the tall and low larkspurs of 

 Colorado. 



DELPHINraM BARBETI Huth. 



Delphinium harbeyi (PI. I) is a perennial, growing from buds at 

 the aj)ex of a long woody root. The stems are pubescent and more 



