(B) Kosin-weed; Compass Plant ( Silphium lacini- 
atum ) is a large, showy-flowered plant found on the 
western prairies. It has a stout, rough, bristly stem 
that attains heights of from three to ten feet. The 
stem grows from a perennial root. The large leaves 
are pinnately divided, each division being linear and 
cut-lobed. 
The flower heads are very large, measuring from two 
to four inches across. They are sessile or exceedingly 
short-stemmed, seated along the upper portion of the 
stout stem. They are disposed to present their edges 
north and south. Compass plant is found on prairies 
from Mich, to North Dakota and southwards; it blooms 
from July until September. 
(A) Prairie Dock (Silphium terbinthinaceum pin- 
natifidium ) is rather an attractive plant that also grows 
on prairies and the edges of copses. The smooth, slen¬ 
der stem ascends 3 to 10 feet high and bears a loose 
panicle of large, yellow-rayed flower heads. The leaves 
mostly come from the root and lower part of the stem; 
they are slender-petioled and deeply pinnatified. Found 
from O. to Minn, and southwards. 
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