242 ELEMENTS OF BOTANY. 



IX. RUDBECKIA. 



Perennial or biennial ; leaves alternate, entire or lobed ; heads 

 radiate, long-peduncled, many-flowered ; bracts imbricated in 

 2-3 series, spreading ; receptacle convex or long-conical, with 

 concave, chaffy scales ; ray flowers yellow, neutral, disk flowers 

 purple to brown, perfect ; achenes smooth, 4-angled, truncate ; 

 pappus a few short teeth or wanting. 



1. R. TRILOBA L. Thin-leaved Cone-flower. Biennial; 

 stem erect, rough-hairy, branched, 2-5 ft. high ; leaves thin, rough 

 on both sides, the lower long-petioled, simple or with 2 lateral lobes, 

 middle leaves short-petioled, deeply 3-lobed or parted, the lobes ser- 

 rate, upper leaves mostly simple, sessile, entire; heads numerous. 

 1-1 i in. wide; bracts narrowly lanceolate, pubescent; ray flowers 

 8-10, disk flowers purplish-black; scales awued, smooth, as long as 

 the flowers ; pappus a few minute scales. June-September. On 

 open gTOund. 



2. R. HiRTA L. CoNE-FLOWER. Usually bieuuial ; stem erect, 

 rough-hairy, simple or branched, 2-3 ft. high; leaves lanceolate 

 to oblong, thick, obscm-ely serrate, hisx:)id, o-ribbed, the lower 

 petioled, the upper sessile ; heads few, loug-peduncled ; bracts hispid, 

 spreading; ray flowers 10-20, orange-yellow, disk flowers purplish- 

 brown ; chaff acute, hairy at the apex ; pappus none. May-August. 

 On dry, open ground. 



3. R. LACiNiATA L. Tall Cone-flower. Perennial; stem 

 smooth, branched, 3-10 ft. high; leaves thin, pubescent or rough- 

 ened, the lower pinnately divided, the lobes irregularly cut and 

 lobed, middle leaves 3-5-lobed or divided, the upper leaves often 

 entire; heads few or many; bracts nearly equal; ray flowers 6-10, 

 yeUow, 1-1^ in. long, disk flowers yellowish ; chaff truncate, pubes- 

 cent at the apex, about as long as the achenes ; pappus of very short 

 scales. June-September. In damp woods. 



X. HELIANTHUS. 



Annual or perennial herbs ; leaves opposite or alternate, 

 undivided, usually 3-ribbed ; heads radiate, few or many, 

 solitary or corymbed ; bracts in several series, the tips spread- 

 ing or appressed ; receptacle chaffy ; ray flowers neutral, disk 

 flowers perfect, tubular; achenes oblong to obovate, com- 

 pressed, 4-angled ; pappus of 2-4 deciduous awns or scales. 



