2 BULLETIN 1212, U. S. DEPARTMENT OF AGRICULTURE. 
In 1898 Chesnut’s Preliminary Catalogue of Poisonous Plants 
was published, in which he makes the following statement : 
Asclepias eriocarpa Benth.—This is the plant with broad mullein-like leaves 
which is known as milkweed in California. Several authentic accounts of the 
poisoning of sheep have been secured against the plant in Mendocino County. 
It is especially feared on very warm days by sheep men when they are com- 
pelled to drive their flocks through dry, barren valleys. It sometimes grows 
on cultivated land and is cut with hay. 
Professor Chesnut had traveled somewhat extensively in Califor- 
nia and had gathered considerable data in regard to the poisonous 
properties of “this plant, upon which the foregoing statement was 
based. In 1902 J. B. Davy, 1 in his bulletin Stock Ranges of North- 
west California, said: “ Several cases of sheep poisoning have been 
recorded against the plant in Mendocino County.” 
In 1910 Pammel, in his Manual of Poisonous Plants, quoted Ches- 
nut as authority for the poisonous properties of Asclepias eriocarpa. 
Jepson, in his Flora of West and Middle California (1911), says 
that Asclepias eriocarpa is said to poison sheep. Other authors have 
mentioned Asclepias eriocarpa as one of the supposed poisonous 
milkweeds, but apparently all the definite information that has been 
published was based largely on the investigations made by Chesnut. 
Recent systematic studies of the species of Asclepias by W. W. 
Eggleston, of the Bureau of Plant Industry, show that probably 
some authors did not distinguish between A. ervocarpa and A. fre- 
montiz, so that the preceding statements do not in all cases refer to — 
the true A. eriocarpa. 
DESCRIPTION OF THE PLANT.1 
Woolly-pod milkweed, Asclepias eriocarpa, shown in Figure 1, is a 
woolly herb with an erect angular stem from 6 inches to 3 feet high. 
It is white-woolly even to the outside of the corolla, becoming de- 
ciduous. The leaves are opposite or three or four together, the upper 
often alternate, broadly oblong to lanceolate, from 4 to 8 inches long, 
obtuse or subcordate at base, rounded or acute at apex, short — 
petioled; the umbels are few or several, on peduncles equaling or 
longer than pedicels; the flowers are creamy- -white, 34 lines long; 
hoods with slight purplish tinge, shorter than the anthers, cleft a 
short distance down the back, the acute sickle-shaped horn little pro- 
truded from between the acute teeth of the cleft. It occurs in dry 
ground. It has been reported from Mendocino and Lake Counties, 
Calif., and extends southward through the coast ranges to the 
southern part of the State. 
The following key will serve to distinguish this milkweed from — 
the nearly related species which are found in California. 
KEY. 
Stems prostrate, strongly flattened______ Solanoa purpurascens (Gray) Greene. 
Stems erect, round in cross section. 
Hoods without horns__---------_- aoe a OM pheeia as 
Plant cishroeuse- is 2.ta-set aptly A eae G. cordifolius Benth. 
Plant, hairy 3. ee ee a oe OT Oris 
1The description of the plant and the accompanying key were prepared by W. W. 
Eggleston, of the Bureau of Plant Industry. 
