COMPOSITAE COMPOSITE FAMILY 
THIN-LEAVED CONEFLOWER 
Rudbeckia triloba L. 
This biennial herb blooms in July and August along with 
many of its relatives in the family. Unlike a goodly number of 
them, however, it prefers rich moist woodlands. Occasionally it 
may be found in cleared 
fields, though it seldom be- 
comes a weed. It is dis- 
tributed through most 
states east of Kansas, ex- 
cept New England. 
A rosette of basal leaves 
appears the first year to 
manufacture food which is 
stored in the roots for use 
the next year. In the second 
year a hairy branching stem 
arises 2-5 feet and bears 
many showy heads. In shade 
the heads are fewer and the 
plant less branching than 
when it grows in the open. 
The lower leaves are dis- 
tinctly petioled and deeply 
3-lobed, whereas the upper 
are shorter stalked or nearly 
or wholly entire. 
The heads are racemosely clustered and nearly 2 inches broad. 
The 8-12 ray flowers are yellow and sterile, having neither 
stamens nor pistils. Each dark purple disk flower is perfect and 
subtended by a sharp-pointed bract or chaff. The linear acute 
bracts of the involucre are hairy and soon reflexed. The 1-seeded 
fruits are smooth and 4-angled, with the pappus a minute crown. 
The Sweet or Prairie Coneflower, Rudbeckia subtomentosa Pursh, 
is an uncommon perennial of prairies and low ground in Illinois. 
The much branched stem is 1-5 feet high and densely covered with 
rough gray hairs. The 15-20 sterile ray flowers are yellow with a darker 
base, and the perfect disk flowers are purplish brown. The chaff is 
blunt and finely hairy or sometimes glandular at the apex. Bracts of 
the involucre are linear-lanceolate with acuminate tips reflexed, and 
are sweet scented. 
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