Isocarfha. COMPOSITE. 257 



90. MELANTHERA, Rohr. (Mc'Xa?, black, and ^ve-qpa, used for anther.) 



— Scabrous herbs (chiefly tropical American) ; with quadrangular branching 

 stems, opposite and sometimes lobed petioled leaves, and pedunculate heads : 

 corolla white and anthers blackish in the genuine (rayless) species. Fl. summer. 



— Rohr, Skriv. Nat. Selsk. Kiob. 1792, ii. 213; DC. Prodr. v. 544. Melanan- 

 thera, Michx. Fl. ii. 106. 



M. hastata, Michx. 1. c. Stem 3 to 6 feet high from a perennial root, spotted : leaves 

 from ovate to ovate-lanceolate, or uppermost lanceolate, some of tliem commonly and vari- 

 ously liastately 3-lobed, unequally serrate : bracts of the involucre broadly lanceolate, of the 

 receptacle spinescently acuminate : heads in fruit half-inch in diameter. — DC Prodr. v. 545. 

 ]\I. triluhuta, panc/uncformis, &c., Cass. Diet. xxix. 485. Bidens nivea, L. Spec. ii. 833 (Dill. 

 Elth. t. 46, 47). Athanasia hastata, Walt. Car. 201. — Moist ground, near the coast, S. Caro- 

 lina to Louisiana. (Mex., W. Ind., &c.) 



M. deltoidea, Michx. 1. c. Leaves ovate to deltoid or obscurely hastate : heads smaller : 

 bracts of the involucre ovate, of the receptacle only mucronate. — DC. 1. c. M. nrtico'folia, 

 Cass. 1. c. M. Linnmi, HBK. Bidens nivea, L. 1. c. as to Dill. Elth. t. 47, f. 3. Galea aspera, 

 Jacq. Ic. Rar. t. 583. — S. Florida. (W. Ind. to S.Am.) 



M. lanceolata, Benth. A foot or two high : leaves lanceolate (1 to 3 inches long, 2 to 5 

 lines wide), somewhat serrate: bracts of the involucre oblong-ovate, of tlie receptacle cuspi- 

 dately mucronate, short: disk about 4 lines in diameter. — Vidensk. Medcl. 1852-3, 88. M. 

 microph////a, Steetz in Seem. Bot. Herald, 156 (same year?). J/. o»y»s;//o//«, A. Rich, ex 

 Griseb. Cat. Cub. 154. — S. Florida, (Jurher, &c. (W. Ind., Centr. Am.) 



91. VAHILLA, Gray. (Native Mexican name of this and some similar 

 plants.) — Shrubby or suffrutescent, glabrous ; with linear and narrow entire and 

 sessile thickish or fleshy leaves, and pedunculate rather small heads, either corym- 

 bosely cymose or solitary; the flowers yellow. — PI. Fendl. 106, & PI. Wright. 

 i. 123. — Two known species. 



V. Mexicana, Gray, 1. c. Shrub about 5 feet high, much branched : branches very leafy, 

 terminated by a cyme of numerous sliort-peduncled heads : leaves not succulent, linear (1 to 3 

 inches long, at most 2 lines wide), attenuate to both ends, opposite : involucre somewhat tur- 

 binate, 2 lines long, half the length of the rather narrow head : pappus of 5 to 10 or 15 slender 

 short bristles (which commonly bear 3 or 4 salient setulose deiiticulations), somewhat irreg- 

 ular, in length fully equal to the diameter of the akene. — Coahuila, near Parras, Gregg, 

 Wislizenus, Palmer, &c., not yet found within U. S. (Mex.) 



V. Texana, Gray. Low, suffrutescent, much branched and very leafy at base : leaves very 

 succulent, terete, mostly alternate, obtuse : head larger, solitary on a long terminal and 

 minutely bracteate peduncle: involucre not turbinate, very much shorter than the broadly 

 ovoid cfuiical disk: pappus none. — PL Wright, i. 103. — Saline soil, from the Nueces to the 

 Rio Grande, S. Texas, Wright, Tre'cul, Bigelow, Palmer. (Adj. Mex.) 



92. ISOCARPHA, R. Br. (From 't'o-o?, equal, Kapcj^o?, chafp, the chaffy 

 bracts of tlie receptacle and of the involucre similar.) ^Tropical American herbs ; 

 with small heads of white or whitish flowers, either solitary or glomerate at the 

 summit of a naked peduncle. — Ti-ans. Linn. Soc. xii. 110; Benth. & Hook. Gen. 

 ii. 365. Dunantia, DC Prodr. v. 626. 



I. oppositifolia, R. Br. 1. c. Pubescent : stems slender, 1 to 3 feet high from a peren- 

 nial?) root, paniculately branched: leaves opposite, lanceolate, narrowed to both ends, 

 triplinerved, entire or sparingly denticulate : heads commonly in threes, in fruit 4 or 5 lines 

 long, narrow, with turbinate involucre : bracts of the involucre and receptacle pointed, becom- 

 ing rigid and the receptacle columnar. — Calea oppositifolia, L. Vunantia Achgrantlies, DC. 

 Prodr. V. 672 ; Deless. Ic. Sel. iv. t. 37. — S. borders of Texas on the Rio Grande, Schott. 

 (Adj. Mex., W. Ind.) 



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