and some succulent species of moist sites are relatively low in palatability, 

 rating poor for cattle and fair for sheep. However, on some of the semi- 

 desert ranges, especially in the Intermountain region, the native species of the 

 groundsel group are more palatable as fall and winter forage,- and are of 

 considerable importance on some of the winter sheep ranges. A great many 

 of the species, especially of the shrubbier sort, have distinctly inferior palat- 

 ability, rating as practically worthless for cattle and poor for sheep. 



In addition to the wide variation in palatability in this genus, the difficulty 

 of evaluating its forage value is increased by the fact that some species are 

 poisonous and have occasionally caused losses of livestock. Broom groundsel 

 (S. spartioi' des) , Riddell groundsel (S. riddel'lii), threadleaf groundsel .(8. 

 longtto'bus, syn. S. filifo'lius), and lambstongue groundsel (8. integer' rimus), 

 among the western species, are definitely known as poisonous. Cattle and 

 horses are more susceptible to poisoning by these plants than sheep, although 

 sheep have been killed by corral feeding of threadleaf groundsel. 3 Broom 

 groundsel and threadleaf groundsel are treated elsewhere in this handbook. 

 Clawson (op. dt.) has shown that threadleaf groundsel is one of the more 

 poisonous of the American species of Scnecrio, and far more likely to cause 

 trouble on the range than lambstongue groundsel. However, since it is seldom 

 grazed, threadleaf groundsel is hardly a source of danger except on depleted 

 or overstocked range. 



The symptoms of Senetio poisoning vary somewhat with the class of livestock 

 and the species. Clawson 3 and Van Es and associates 4 have noted that usually 

 there is a tendency for horses and cattle to avoid other animals, and to display 

 marked signs of depression, impaired sensibility, yawning, lack of appetite, 

 weakness, uneasiness, as well as an inclination to chew various articles other 

 than food, the tendency to run into and push against objects, and, in the later 

 stages, to engage in almost constant aimless wandering. In some cases a con- 

 gestion and yellowish discoloration of the mucous membranes develops, usually 

 accompanied by a peculiar, sweetish, sickening odor emanating from the skin, 

 especially about the head, neck, and shoulders. Cattle exhibit quite similar 

 symptoms ; sometimes areas of skin evidently irritate the animal as shown by 

 its attempts to rub the affected spots which, on occasion, literally ooze serum. 

 Some animals are constipated ; others evidence a mild diarrhea. 5 Clawson 3 

 reports that the only visible symptoms observed in affected sheep were "depres- 

 sion, weakness, loss of appetite, a more or less jaundiced condition * * * 

 (and) in some instances, evidences of abdominal pain and spasmodic muscular 

 twitching were noted." 



Riddell groundsel (8. riddel'lii), a smooth perennial herb with leafy, branched 

 stems about 12 to 40 inches high, occurs chiefly on the plains from Wyoming 

 and Nebraska to Texas and New Mexico. Its hairless leaves are divided into 

 narrow, linear segments, and the numerous hairless flower heads, about three- 

 eighths of an inch high, are borne in somewhat flat-topped clusters. The from 

 12 to 20 main bracts at the base of the flower head are hairless, narrow, 

 somewhat keeled, and pointed, forming a bell-shaped involucre. A few very 

 short, small bractlets are present at the base of the involucre. Its approxi- 

 mately 12 petallike ray flowers are bright yellow and about three-eighths to 

 one-half of an inch long; the body of the seedlike fruits (achenes) is some- 

 what hairy. Riddell groundsel is the cause of the so-called walking disease of 

 northwest Nebraska. 4 



Lambstongue groundsel (8. integer 'rimus, syns. S. dis'par, /S. exalta'tus, S. 

 lu'gens, 8. perplex' us) ranges in the sagebrush, pinon, and ponderosa pine belts, 

 from Minnesota to British Columbia, California, and Colorado. It is a variable 

 species, with leafy stems branched above and 12 to 40 inches high. The lower 

 leaves are stalked and vary in shape from reverse-egg-shaped to reverse-lance- 

 shaped, being hairless or sparsely hairy when young and much larger than the 

 stalkless, lance-shaped to linear stem leaves. The flower heads are numerous, 

 about three-eighths to five-eighths of an inch high and nearly as wide, with 

 those of the terminal cluster borne on shorter stalks than those of the lateral 



8 Clawson, A. B. THE AMERICAN GROUNDSELS SPECIES OP SENECIO AS STOCK POISONING 

 PLANTS. Vet. Med. 28 (3) : 105-110, illus. 1933. 



4 Van Es, L., Cantwell, L. R., Martin, H. M., and Kramer, J. ON THE NATURE AND 



CAUSE OF "THE WALKING DISEASE" OF NORTHWESTERN NEBRASKA. NECROBIOSIS ET 



CIRRHOSIS HEPATIS ENzooTiCA. Nebr. Agr. Expt. Sta. Research Bull. 43, 47 pp., illus. 

 1929. 



