236 COMPOSITE, (composite family.) 



involucre oblong-linear ; rays wedge-shaped, palmately 3-lobed ; ovary wingless, 



with hispid margins. — River-hanks, South Carolina and Georgia. September. 



— Stem 2° -3° high, 



■*- •*- ■*- Rays purple or rose-color. 



16. C. nudata, Nutt. Smooth ; stem slender, forking above ; leaves al- 

 ternate, distant, terste, and rush-like ; rays bright purple, 3-toothed ; achenia with 

 lacerated wings, 2-awned. — l'ine-barrtii ponds, Florida and Georgia, near the 

 coast. April. — Stem 2° high. Lowest leaves 1° long. Kays 1' long. 



17. C. rosea, Nutt. Smooth; stem low, branching; leaves opposite, lin- 

 ear; heads small; rays slightly 3-toothed ; achenia wingless, unawned. — 

 Swamps, Georgia, Nuttall, and northward. July and August. — Stem 8'- 12' 

 high. Rays rose-color. 



18. C. CEmleri, Ell. Leaves broad-lanceolate, sessile, acnte at each end, 

 entire: peduncles axillary and terminal, dichotomously corymbose. — Collected 

 mar the junction of the Broad and Saluda Rivers by Mr. Gimler. Elliott. — 

 Stem 2° -3° high, angular, smooth. Leaves connate by a small membrane. 

 Heads small. Rays about 8, entire. Achenia wedge-shaped, slightly 2-toothcd 

 and margined. ( * ) 



51. COSMOS, Cav. 



Scales of the involucre more or less united. Aehenia terete or 4-angled, nar- 

 rowed or beaked at the apex, and crowned with 2-4 downwardly barbed or 

 hispid deciduous awns. Otherwise like Coreopsis. — Leaves opposite, pinnately 

 divided. Disk yellow. Rays purplish. 



1. C. caudatus, Knnth. Smooth ; leaves bipinnately divided, with the 

 divisions lanceolate and entire ; achenia (1'long) tapering into a very long rough 

 beak, 2-awncd ; rays short, 3-cleft, rose-color. — Key West, Florida. 



52. BIDENS, L. Beggajmticks. 



Chiefly like Coreopsis-; but the exterior involucre often long and leaf like ; 

 the aehenia compressed, or 3 -4-angled, (not narrowed at the apex.) and crowned 



with 2-4 persi-tent downwardly barbed or hispid awns. — Leaves serrate, or 

 pinnate]; divided, opposite. Rays yellow or white, often wanting. Disk 



yellow. 



* Achenia JtaUened, narrowly toedg&shaped. 

 i. B. frondosa, L. Stem tall, branched ; haves thin, long-petioled, pin- 

 nately 3 - 5-divided ; the divisions ovate or ovate lanceolate, acuminate, sharply 

 Bcrrate; heads discoid; exterior scales of the involucre large, leafy; achenia 

 2-awned — Low ground, Florida and northward. July-Sept. CD — Stem 



2° -5° high. Mai -ins of the aehenia upwardly eiliate. 



2. B. connata, Muhl, Stem low, branched; haves oblong-lanceolate, 

 acuminate, coarsely serrate, tapering and connate at the bale, the lowesl often 

 3-parted ; headi discoid . exterior involucre leafj ; achenia l-4««wned, with 

 downwardly hispid margins. — "WeBtern district* of Georgia and westward, in 



damp Mfl diil_\ - Sept. i , — Stem 1^-2° high. 



