350 COMPOSITiE. Cosmos. 



cuspidate ; scales of the involucre scarcely united ; the exterior linear-lanceo- 

 late, cuspidate, ciliate, spreading, nearly equalling the scarious or colored in- 

 terior series; chaff' obtuse ; achenia 4-angled, tapering into a very long up- 

 wardly scabrous beak, crowned with 2 spreading awns. — H. B. ^' K. nov. 

 gen. ^' sjjec. 4. |>. 240 ; DC. ! prodr. 5. ^j. 606. JBidens Berteriana, Spreng. 

 sysl. 3. p. 454 ; DC. ! in Wight, conlrib. p. 19. 



Key West, Mr. Blodgett! A common West Indian species ; also natur- 

 alized in the East Indies. — li Rays rose-color, 3-cleft at the summit, 

 scarcely longer than the involucre. Achenia (about 20) nearly an inch 

 long. 



103. COSMIDIUM. Torr. &; Gray, mss. ; Nutt. in trans. Amer. phil. 

 soc. {n. ser.) 7. p. 361. 



Heads many-flowered ; the ray-flowers about 8, neutral, or sometimes 

 wanting ; those of the disk tubular, perfect. Involucre double, each of 8 

 scales; the interior oblong-ovate, somewhat membranaceous, united' to the 

 middle, much larger than the exterior. Receptacle flat ; the chaff" scarious, 

 oblong, obtuse, with 2 approximate colored nerves, shorter than the flowers, 

 partly investing the achenia, and deciduous with them. Corolla of the disk 

 with a very slender tube, and a deeply 5-cleft limb; the segments long and 

 linear, recurved. Anthers and style as in Cosmos (the base of (he latter 

 dilated into a conspicuous bulb.) Achenia linear-oblong (obscurely angled 

 when young), terete or slightly obcompressed, a little incurved and tubercu- 

 late on the back when mature, not rostrate, the abrupt summit crowned with 

 2 dentiform retrorsely pectinate-ciliate (persistent ?) awns. — Annual and pe- 

 rennial dichotomous or brachiate glabrous herbs, with slender branches naked 

 at the summit, and term.inated by rather small heads. Leaves opposite, 

 somewhat fleshy (the lower petioled, the upper nearly sessile), 1-2-pinnate- 

 ly parted ; the divisions or lobes linear-filiform, canaliculate, entire. Rays 

 light yellow ; the disk-flowers purple : the chaflf white. 



1. C. jilifolium (Torr. & Gray ! 1. c.) : lower leaves twice ternately or 

 pinnately divided; the upper simply 3-5-divided, or the uppermost siinple ; 

 the divisions attenuate-filiform ; scales of the interior involucre with broad 

 scarious margins, united nearly to the middle, longer than the linear-subu- 

 late exterior scales; rays obovate, 3-toothed ; achenia crowned with 2 trian- 

 gular-subulate concave at length divaricate short awns or teeth. — Nutt.! I. c. 

 Coreopsis filifolia. Hook.! hot. mag. t. 3505; DC! 2>i'odr. 7. p. 290. 



Plains of Arkansas, on the Red River, &c., Nuttali ! Dr. Leavenworth ! 

 Dr. Engelmann ! Te\ns, Drtimmond ! May-July. — (T) Hook. H Nutt. 

 Stem 1-3 feet high, much branched. Heads nearly as large as in Coreopsis 

 tinctoria. Achenia about 3 lines long, crustaceous when ripe, one or both 

 sides smooth and even when young: the awns or teeth scarcely a line in 

 length, fringed with yellow reflexed bristly hairs, apparently persistent. Chaflf 

 closely investing the back of the achenia. — We had provisionally appended 

 this group to Cosmos (not to Coreopsis, as Mr. Nutiall by some misappre- 

 hension states), to which it is most allied, notwithstanding the yellow rays 

 (which are also found in C. sulphureus) and erostrate achenia. 



2. C. gracile (Torr. & Gray ! I.e.): leaves pinnately or pedately about 

 5-parled, with narrowly linear rigid lobes; the uppermost nearly simple; 



