COMPOSITES. (COMPOSITE FAMILY.) 135 



clothed with uncinate-tipped prickles : each flower a single pistil, maturing a thick 

 ovoid akene, the two permanently enclosed in the indurated prickly involucre. Leaves 

 alternate. 



* * * Ray-flowers ligulate and fertile ; the ligule with very short tube or none, persistent 



on the akeue and becoming papery in texture : disk-flowers hermaphrodite and fertile, 

 numerous, subtended or embraced by chaffy bracts ; the corolla cylindraceous : leaves 

 opposite and heads singly terminating the stem or branches. 



+- Leaves all or mostly entire, sessile : akenes of the disk compressed, all or some of them 

 toothed or awued from the summit of the angles or edges. 



31. Zinnia. Involucre campanulate or cylindraceous: its closely appressed-imbricated 

 bracts dry and tirm, broad, with rounded summit often margined. Receptacle becoming 

 conical or cylindraceous : the chaffy bracts couduplicate arouud the disk-flowers. Lobes 

 of the disk-corolla mostly velvety-villous. Pappus when present of erect awns or 

 chaffy teeth. Rays showy. 



t- +- Leaves commonly serrate, slender-petioled : akenes not compressed. 



32. Heliopsis. Involucre short, of nearly equal oblong or lanceolate bracts. Receptacle 



from high-convex to conical : the pointless chaffy bracts partly embracing the disk- 

 flowers. Ligules large : disk-corollas glabrous. Akeues obtusely 4-angular, with 

 broad truncate summit, wholly destitute of pappus. 



* * * * Ray-flowers ligulate and either fertile or neutral, or even wanting, the ligule 



not persistent: disk-flowers hermaphrodite and fertile, subtended and sometimes 

 enwrapped by the chaff: pappus a cup or crown, of teeth or awns from the 2 to 4 

 principal angles, or of a few stout bristles, or none. 



-- Receptacle high, from conical to columnar or subulate, at least in fruit. 



33. Echinacea. Involucre imbricated in 2 or 3 or more series : its bracts lanceolate. 



Disk at first only convex, becoming ovoid and the receptacle acutely conical : chaffy 

 bracts of the latter persistent, carinate-concave, acuminate into a rigid and spinescent 

 cusp. Ligules rose-colored or rose-purple. Disk-corollas cylindraceous, with 5 erect 

 teeth and almost no proper tube. Akenes acutely quadrangular, somewhat obpy- 

 ramidal, with a thick coroniform pappus more or less extended into triangular teeth 

 at the angles. 



34. Rudbeckia. Involucre looser, spreading, more foliaceous. Disk from hemispheri- 



cal or globose to columnar, and receptacle from acutely conical to cylindrical : its 

 chaffy bracts not spinescent, but sometimes soft-pointed. Ligules yellow or partly 

 brown-purple. Disk-corollas with a short but usually a manifest proper tube. 

 Akenes 4-angled, prismatic. Pappus a coriaceous and often 4-toothed crown, some- 

 times none. 



35. Liepaehys. Akenes short and broad, compressed, acutely margined or sometimes 



winged at one or both edges, on a slender-subulate receptacle. Pappus a chaffy tooth 

 over one or both edges, or none. Chaffy bracts of the receptacle conduplicate, with 

 thickened and truncate summit, embracing and hardly surpassing the akenes, at 

 length deciduous with them. Corollas of the disk with hardly any proper tube. 

 Ligules, involucre, &c. of Rudbeckia. 

 t- - Receptacle from flat to convex, or in certain species conical : akenes not winged nor 



very flat, when flattened not margined or sharp-edged. 



M- Rays fertile : receptacle flat or merely convex : ray akenes commonly triquetrous or ob- 

 compressed : pappus persistent or none. 



36. Balsamorrhiza. Akenes destitute of pappus, oblong : of the disk quadrangular 



and often with intermediate nerves. Involucre broad : the outer bracts foliaceous, 

 sometimes enlarged. Chaff linear-lanceolate- Tuberous-rooted low herbs. 



37. Wyethia. Akenes prismatic, large, 4-angled, or in the ray 3-angled and in the disk 



often flattened, also with intermediate salient nerves. Pappus a lacerate chaffy crown, 

 or cut into nearly distinct scales, commonly produced at one or more of the angles 

 into chaffy rigid awns or teeth. Involucre campanulate or broader, more or less im- 

 bricated : outer bracts often foliaceous. Chaff lanceolate or linear, partly embracing 

 the akenes. Thick-rooted and large-headed herbs, witli alternate leaves. 



