RAYLESS GOLDENROD AS A POISONOUS PLANT 5 
bacterium. It has been shown, however, by Marsh and Clawson 
(5, 6), Curtis and Wolf (7), and Wolf, Curtis, and Kaupp (9), that 
most cases of so-called milk sickness of domestic animals in the 
eastern United States are caused by Eupatorium ur tic ce folium. It 
may be interesting to note in this connection that the chemical study 
of these two plants by J. F. Couch, of the Bureau of Animal In- 
dustry, which is now in an advanced state, shows conclusively that 
the toxic substances in the two plants are not the same. 
Inasmuch as the disease in the Pecos Valley has been generally 
considered as connected with the so-called rayless goldenrod (Aplo- 
pappms heterophyllus) and by many has been considered to be the re- 
sult of intoxication by this plant, it was considered of great im- 
portance to determine conclusively whether the plant has toxic prop- 
erties for livestock. It certainly is a very unusual state of things 
for two distinct plants, growing in widely separated parts of the 
country, to produce similar poisonous effects on domestic animals. 
It was with the intention of proving definitely and finally whether 
Aplopappus heterophyllus was poisonous or not that the feeding 
experiments detailed in this bulletin were undertaken. 
DESCRIPTION OF THE PLANT 5 
Aploppappus heterophyllus, shown in Figure 1, belongs to the 
Composite family, in which the flowers are in compact heads, the 
heads being often mistaken for real 
flowers, as in the case of the sun- 
flowers. It is commonly called 
rayless goldenrod, but in some lo- 
calities the term " jimmy weed " 
is used. 
The plant is a stout, erect, tufted 
perennial herb with shrubby or 
near shrubby base, minutely hairy 
to nearly smooth, commonly from 
1 to 2 feet in height, but sometimes 
under favorable circumstances of 
growth, as on the banks of irrigat- 
ing ditches, it may reach a height 
of 4 feet or even more. 
The leaves are alternate, linelike 
or broader, one-eighth to one- 
fourth inch wide, three-fourths to 
2y 2 inches long, usually with stout, 
stiff hairs on the margin, occasion- 
ally with short, sharp, scattered 
teeth, and acute or obtuse at the apex. 
The heads are numerous, with or 
without stems, in terminal flat- 
topped bunches; the bracts surrounding the flower heads are about 
one-eighth inch high, oblong, usually obtuse, with obscurely green 
tips. The heads have 7 to 15 tubular yellow flowers. The seeds are 
silky and small. 
Fig. i. 
single plant of 
heterophyllus 
Aplopappus 
5 The description of the plant was prepared by W. W. Eggleston, of the Bureau of Plant 
Industry. 
