COMPOSITAE 



COMPOSITE FAMILY 



THIN-LEAVED CONEFLOWER 



Riidbeckia 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 1 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 i -seeded 

 fruits are smooth and 4-angled, with the pappus a minute crown. 



The Sweet or Prairie Coneflower, Riidbeckia 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 1 5-20 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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