286 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



28. ECLIPTA L. 

 1. Eclipta alba (L.) Hassk. 



Wet ground; common along the Potomac. July-Oct. Widely distributed in the 

 U.S., doubtless naturalized northward ; common in most tropical regions. ( Verbesina 

 alba L.; E. procumbent Michx.) 



An inconspicuous annual with small heads of white flowers. 



29. RUDBECKIA L. 



Stems glabrous, or with a few minute appressed hairs just below the heads; rays 

 drooping, bright yellow; receptacle elongate in fruit; disk flowers greenish 



yellow; lower leaves pinnately lobed 1. R. laciniata. 



Stems copiously hairy; rays spreading; receptacle not elongate in fruit; disk flowers 

 deep purple; leaves 3-lobed or merely toothed. 

 Chaff of the disk long-acuminate, glabrous; lower leaves 3-lobed, sparsely hairy. 



Rays orange-yellow .' 2. R. triloba. 



Chaff of the disk obtuse or acutish, pubescent; leaves merely toothed or entire. 

 Chaff of the disk densely and finely hairy; rays bright yellow; leaves densely 



hairy; pappus none 3. R. hirta. 



Chaff of the disk minutely hairy on the margin, otherwise glabrous; rays usually 

 or^ige-yellow; leaves sparsely hairy; pappus a low crown 4. R. fulgida. 



1. Rudbeckia laciniata L. Tall cone-flower. 

 Wet soil, often at the edge of water; common. Aug.-Oct. Widely distributed in 



N. Amer. 



The golden glow, so common in cultivation, is a form of this species with -'double" 

 flowers, that is, the usually inconspicuous disk flowers have assumed the form of rays. 

 Double-flowered plants are sometimes found wild. 



2. Rudbeckia triloba L. 



Woods along the Potomac above Washington. July-Oct. Eastern U. S. 



3. Rudbeckia hirta L. Black-eyed Susan. 

 Woods and open fields; common. June-Sept. Nearly throughout the U. S. and 



southern Can.; adventive eastward. 



4. Rudbeckia fulgida Ait. Orange cone-flower. 

 Dry woods; common. Aug.-Oct. Southern states, north to N. J. 



The plants are somewhat variable, especially in leaf form, probably as a result of 

 varying conditions as to moisture and light. 



30. HELIANTHUS L. Sunflower. 



Leaves linear or nearly so, entire, sessile or subsessile. Stems hairy below and about 

 the inflorescence; diBk flowers purple; bracts linear-lanceolate, scabrous. 



1. H. angustif olius . 



Leaves lanceolate or broader, usually toothed. 



Stem leaves sessile, opposite. 

 Stems glabrous except about the inflorescence; leaves spreading, lanceolate, 



sparsely hairy beneath, truncate at the base 2. H. divaricatus . 



Stems densely hairy; leaves ascending, ovate, densely soft-hairy beneath, cordate 



at the base 3. h. mollis. 



Stem leaves petioled. 

 Plants annual; leaves alternate; disk of the head 2.5 cm. wide or often much 

 broader. Stems hairy 4. H. annuus. 



