BiDENs. COMPOSlTiE. 389 



§ 2. PsiLOCAKF£A, DC. Achenio, linear-tetragonal, attenuate or rostrate, smooth or upwardly 



hairy. 



6. BiDENS BiPiNNATA, Linn. Spanish Needles. 



Stem quadrangular ; leaves petioled, 1 - 3-pinnately divided, the segments lanceolate or 

 oblong-ovate ; heads on long slender peduncles, usually v?ith 3-4 small rays ; exterior scales 

 of the involucre linear, spreading, about the length of the interior ; achenia linear, elongated 

 and slender, nearly smooth, mostly 4-awned. — Linn. sp. 2. p. 832 ; Michx. Jl. 2. p. 135 ; 

 Pursh, fl. 2. p. 567 ; Ell. sk. 2. p. 432 ; Torr. compend. p. 312 ; Beck, hot. p. 207 ; Dar- 

 lingt. fl. Cest. p. 487 ; DC. prodr. 5. p. 603 ; Torr. ^ Gr. fl. N. Am. 2. p. 354. 



Annual. Stem 1-2 feet high, slender, smooth, branching. Leaves smooth, on slender 

 petioles. Heads small, in a loose paniculate corymb. Interior scales of the involucre lanceo- 

 late. Rays 3-4, obovate, bright yellowr. Disk-flowers yellow, 15 - 20. Achenia a little 

 tapering upward, crowned with 4 unequal slightly spreading awns. 



Waste places, road-sides and cultivated grounds ; common in the neighborhood of New- 

 York and along the Hudson, but rare iij the interior of the State. July - October. Probably 

 introduced from the Southern States. 



Subtribe III. Helenie^, Cass., DC. Heads mostly heterogamous and radiate ; the disk- 

 flowers perfect, but sometimes sterile : receptacle naked or chaffy. Anthers often blackish ; 

 the lobes frequently produced at the base, but scarcely caudate. Pappus chaffy ; the 

 scarious scales several or numerous and distinct, or sometimes none. — Leaves alternate 

 > or opposite. 



28. HELENIUM. Linn. ; Lam. ill. t. 688 ; Endl. gen. 2603. FALSE sunflower. 



[ Named after Helen, the wife of Menelaus, who used a plant allied to this as a coBmetic] 



Heads many-flowered, radiate ; the ray-flowers in a single series, pistillate, ligulate, cuneiform, 



3 - 5-cleft at the summit. Disk-flowers with a very short proper tube, and a large inflated 



4 _ 5-toothed limb. Scales of the involucre in two series ; the exterior linear or subulate, 

 foliaceous, spreading or reflexed ; the interior much shorter and chaify. Receptacle convex, 

 chaffy. Branches of the style obtuse. Achenia obovate-turbinate, villous on the ribs. 

 Pappus of 5 - 8 chaffy and often awned scales. — Branching herbs, with alternate leaves 

 which are decurrent on the angular stem. Flowers yellow, very bitter ; the rays often 

 purplish toward the base. 



1. Helenium autumnalb. Sneeze-weed. 



Smoothish ; leaves lanceolate, serrate, strongly decurrent ;- scales of the involucre linear- 

 subulate ; rays flat, 3 - 5-toothed at the extremity, longer than the globose disk ; scales of 

 the pappus ovate-lanceolate, cuspidate, about one-third the length of the corolla. — Linn. sp. 



