448 COMPOSITAE (COMPOSITE FAMILY) 
on the long, naked stalks near 
their summits; the many rays 
long, yellow, notched at their tips, 
pistillate and fertile ; disk-florets 
orange-yellow, perfect but ster- 
ile; bracts of the involucre nar- 
rowly ovate with long, stiff 
points spreading nearly as wide 
as the rays. The achenes, being 
the fruit of the ray florets, are 
in rings around the outer edge 
of the heads, each about a half- 
inch long, brown, flat, oval, and 
broadly winged, deeply notched 
at the top, without pappus. 
(Fig. 312.) 
Means of control 
Cultivation of the ground is 
the best method of suppres- 
M sion; but if not desirable to 
Fic. 312. — Compass Plant (Stlphium break up the meadows where 
laciniatum). x . the plant is most troublesome, 
it should be cut deeply, below the crown, with a sharp hoe or 
spud, before the first flowers mature, the roots being salted so as to 
check new growth. 
PRAIRIE DOCK 
Stlphium terebinthindceum, Jacq. 
Other English names: Rosin Plant, Prairie Burdock. 
Native. Perennial. Propagates by seeds. 
Time of bloom: July to September. 
Seed-time: August to October. 
Range: Ontario and Ohio to Minnesota, southward to Georgia and 
Louisiana. 
Habitat: Prairies and dry woods, meadows, and pastures. 
Terebinthine is the ancient word for turpentine, and the resin- 
ous juice of this and the preceding weed accounts for one of their 
