136 COMPOSITE. (COMPOSITE family.) 



♦+ 4+ Bays sterile, rarely wanting: akenes quadrangular-compressed or more turgid : chaffy 

 bracts of the convex or conical receptacle embracing the akenes. 



38. Gymnoloniia. Pappus none or a minute denticulate ring: the truncate apex of the 



short akenes commonly at length covered by the base of the corolla, the tube of 

 which is usually pubescent. 



39. Heliaiithiis. Pappus deciduous, of two scarious and pointed scales, mostly no in- 



termediate ones. Akenes usually glabrous or glabrate. Tube of the disk-corollas 

 short, and the throat elongated. 

 4--t-4- Receptacle flat, convex, or sometimes becoming conical : akenes of the disk either 

 flat-compressed and margined or thin-edged, or if turgid some of them winged : pappus 

 not caducous. 



40. Helianthella. Rays neutral, rarely wanting. Pappus of delicate scales between the 



two chaffy teeth or awns which surmount the two acute margins of the akene, or these 

 obsolete in age. Ovary often wing-margined, but mature akene not so. 



41. Verbeslna. Involucre canipanulate or hemispherical, imbricated. Rays fertile, 



sometimes neutral or none. Akenes usually winged and flat, 2-awned, or in the ray 

 1 to 3-awned, with no intermediate scales, and even the awns sometimes wanting. 

 Leaves apt to be decurrent as wings on the stem. 

 ***** Akenes obcomprcssed or sometimes terete, and the subtending chaffy bracts flat 

 or hardly concave; otherwise as in the last section: heads many-fluwered : leaves 

 mostly opposite : style-tips of the disk-flowers produced into a cusp or cone : invo- 

 lucre double : receptacle flat or merely convex: rays in ours neutral. 

 •*- Akenes never with retrorsely barbed awns. 



42. Coreopsis. Involucre of two distinct series of bracts, all commonly united at the 



very base ; outer foliaceous, narrower, and usually spreading ; inner erect or incurved 

 after blooming, each series commonly 8 in number. Rays about 8. Akenes flat, or- 

 bicular to linear-oblong, winged or wingless, truncate or emarginate at summit, bearing 

 2, rarely 3 or 4 naked awns, scales, or teeth, or sometimes destitute of pappus. 

 +- 4- Awns of the pappus when present retrorsely barbed or hispid. 



43. Bidens. Bracts of the involucre distinct, or united only at the common base. Akenes 



neither winged nor beaked, 2 to 5-awned : the awns retrorsely hispid, Rays neutral, 

 yellow or white, sometimes wanting. 



44. Thelesperma. Bracts of the inner involucre united into a cup ; outer of shorter 



and narrow bracts, connate at base with the inner. Chaff of the flat receptacle white- 

 scarious. Rays about 8, cuneate-obovate. Disk-corollas with long and slender tulie, 

 and abrupt campanulate or cylindrical throat. Anthers wholly exserted. Akenes 

 slightly obcompressed or terete, narrowly oblong to linear, marginless, beakless : the 

 abrupt summit crowned with a pair of persistent and stout awns or scales, or some- 

 times pappus wanting. Leaves opposite. 

 * * * # * # Ray-flowers ligulate and fertile, each subtended by a bract of the mostly one- 

 seried involucre which more or less encloses its akene : disk-flowers hermaphrodite, but 

 some or all of them sterile, their style-branches subulate and hispid : chaff always 

 present between ray and disk flowers : pappus none to the ray-akenes, chatfy or else 

 none to the disk-flowers : commonly glandular-vis oid and heavy-scented herbs. 



45. Madia. Heads many to several-flowered. Involucre ovoid or oblong, few to many- 



angled by the salient narrow backs of the involucral bracts. Receptacte flat or con- 

 vex, bearing a single series of bracts enclosing the disk-flowers as a kind of inner 

 involucre, either separate or connate into a cup. Ray-flowers 1 to 20, with cuneate 

 or oblong 3-lobed ligules : their akenes laterally compressed, and enclosed in condu- 

 plicate-infolded involucral bracts. 

 16. Layia. Heads many-flowered, broad : ray-flowers S to 20, with S-lobed or toothed 

 ligules. Bracts of the involucre flattened on the back below, with abruptly dilated 

 thin margins infolded so as to enclose the ray-akene. Reneptacle broad and flat, 

 bearing a series of thin chaffy bracts between the ray- and disk-flowers. Akenes of 

 the ray obcompressed, almost always smooth, destitute of pappus ; those of the disk 

 similar or more linear-ouneate, mostly pubescent, bearing a pappus of 5 to 20 bristles 

 or scales, or rarely none. 



