46 



BULLETIN" 12 45, U. S. DEPARTMENT OF AGRICULTURE 



A somewhat peculiar characteristic of coyotillo poisoning is that 

 while it may result from a single feeding, the symptoms may not 

 appear for several days or even weeks. Cases of serious poisoning 

 of children have also been reported. 



THE PARSLEY FAMILY (APIACEAE) 



WATER HEMLOCK (SPECIES OF CICUTA) 



The most poisonous of all the plants in the United States are, with- 

 out any doubt, the water hemlocks belonging to the genus Cicuta. 

 They are commonly but erroneously known throughout the West as 

 parsnip. Several species of Cicuta are recognized by botanists, but 

 they are very closely allied, and for the purpose of stockmen the 

 description of one will serve for all. Plates 31 and 32 show tuber 

 water hemlock, Cicuta vagans, the species which is common on the 

 Pacific slope, while Plate 33 shows the stems and roots of the species 



growing further east, 

 spotted water hemlock, 

 C. maculata. 



Cicuta is an umbel- 

 liferous plant growing 

 in swamps and damp 

 valleys and frequently 

 very abundantly along 

 irrigating ditches. A 

 large number of umbel- 

 liferous plants occur in 

 these localities, and it 

 is difficult for one un- 

 acquainted with botany 

 to distinguish Cicuta 

 from similar but non- 

 poisonous plants. Prob- 

 ably the easy way to 

 distinguish the plant is by an examination of the rootstock. The 

 Cicuta grows from a rootstock to which are attached roots which may 

 be small (pi. 32), or may take the form of a group of thick, fleshy 

 tubers (pi. 33). In longitudinal section this rootstock shows more 

 or less distinctly a number of transverse chambers. (PL 32.) By 

 this peculiarity of structure Cicuta can be distinguished from most 

 plants growing in places where it is likely to be found. 



Poisoning by Cicuta 



It has been commonly thought that the tops of Cicuta when found 

 in hay caused the loss of stock, but experimental work of the depart- 

 ment has shown quite conclusively that the mature tops and seeds 

 never occasion losses, although cases of poisoning have resulted from 

 eating the young shoots in the spring. The rootstock and roots are 

 violently poisonous and a very small quantity is sufficient to kill any 

 animal that eats them. Probably all animals are susceptible to the 

 effects of this plant. The losses of domestic animals are mainly of 

 cattle which either obtain the rootstocks that have been plowed up 



Figure 21. — A plant of coyotillo, Karwinskia humboldt 

 iana, at the time of blossoming 



