Melanthera. composite. 297 



* * Achenia, at least those of the disk, compressed. 



107. Spilanthes. Receptacle conical. Appendages of the style truncate. Rays 



deciduous, often none. 



108. LipocHJETA. Receptacle flattish. Achenia awned from the angles, and witli 



chaffy or squamellate teeth between the awns. 



109. Verbesina. Receptacle flattish. Achenia 2-awned. Rays few or none. 



110. XiMENEsiA. Receptacle convex. Achenia of the disk •2-awned and winged. 



of the ray wingless. Rays numerous. 



111. Sanvitalia. Receptacle convex. Achenia of the ray 3-sided and 3-awned, 



of the disk compressed, scarcely awned. Rays persistent. 



Div. 1. Heiiopside^, DC. — Rays pistillate and fertile (in Melan- 

 thera none), ligulate. Achenia never obcompressed (that is, flattened) paral- 

 lel with the scales of the involucre or chaff of tlie receptacle ; the exterior 

 integument (calyx-tube) thick and firm, often separable from the interior. 

 Pappus none, or coroniform, frequently toothed or with one or more rigid 

 awns. 



83. MELANTHERA. " Rohr, in Kioh. nat. hist, selsk. 2. (1792) p. 

 213";* Cass., in jour. phys. 1823, DC. prodr. 5. pi- 544. 



Melananthera, Michx. ^-c. 



Heads discoid, many-flowered ; the flowers all tubular and perfect. Scales 

 of the involucre in a double series, nearly equal. Receptacle convex ; the 

 persistent chaff partly sheathing the flowers. Teeth of the corolla papillose. 

 Branches of the style hispid above, acuminate. Achenia .short, compressed- 

 quadrangular, or sometimes triangular, truncate at the summit. Pappus of 

 2-18 rather rigid scabrous caducous bristles or awns. — Perennial herbaceous 

 or rarely suffrutescent (American, tropical) scabrous plants, with quadrangu- 

 lar branching stems. Leaves opposite, or rarely ternately verticillate, pe- 

 tioled, Iriplinerved, toothed or serrate, often 3-lobed. Heads ternate or soli- 

 tary, peduncled. Corolla white. Anthers black with whitish appendages. 



1. M. hastata (Michx.) : leaves opposite, very scabrous, mostly hastate- 

 3-lobed ; scales of the involucre lanceolate; chaff of the receptacle acumi- 

 nate-cuspidate ; awns of the pappus 2-3. — DC. I ijrodr. 5. p. 545. M. tri- 

 lobata & pandura3formis, Cass. in. diet. I. c. 29, p. 485. Melananthera has- 

 tata, iWjc/ix. .' ^. 2. p. 107; Pursh! fl. 2. p. 519; Ell. sk. 2. p. 315. 

 Bidens nivea, (3. & y. Linn, (ex syn. Dill. Elth. t. 49 4' 47); Walt. Car. 

 p. 201 1 Athanasia hastata, Walt.! I. c. 



Dry soil, S. Carolina! to Florida! and Louisiana! (Also in Cuba, La 

 Sagra, ex DC.) July-Sept. — Stem 4-6 feet high, often beautifully marbled 

 or spotted. Leaves variable in form, between lanceolate and deltoid-ovate, 

 either deeply or slightly hastate-3-lobed, or somewhat pandurilbrm, some- 

 times undivided, acute or acuminate. Epigynous disk or nectary rather con- 

 spicuous, sheathing the base of the style. 



♦ Transactions of the Natural History Society of Copenhagen. 

 VOL. II. — 38 



