COMPOS ITiE. 65 



Akenes thick, in the ray mostly 3-sided and in the disk compressed, more or less margined, 

 without pappus, or sometimes with 2 to 4 teeth or short awns. Leaves opposite and heads 

 small. 



H— -1— -(^ Bracts of the many-flowered receptacle concave or complicate, loosely embracing 

 or subtending the disk-akenes, mostly persistent. 



++ Bays uniformly none, the flowers all hermaphrodite and fertile : involucre dry or partly 

 so : akenes not flat nor margined : pappus of slender awns or none. 



90. MELANTHERA. Involucre hemispherical; the disk in fruit globular, and squarrose 

 with the JBostly pointed rather rigid striate concave bracts of the convex or low-conical 

 receptacle ; bracts of the involucre ovate to lanceolate, thickish, nerveless, in 2 or 3 series, 

 somewhat equal in length. Corolla 5-lobed, with campanulate-oblong ampliate throat. 

 Style-branches tipped with a subulate hispid appendage. Akenes thick and .short, com- 

 pressed-quadrangular, somewhat obpyramidal, with broad truncate summit : pappus of 2 or 

 more slender caducous awns. Leaves opposite, petioled. 



9 1 . VARILL A. Involucre short, of rather few and small linear-lanceolate appressed-imbri- 

 cate and mostly few-striate bracts, similar to those of the at length high-conical or oblong 

 receptacle. Corolla with narrow cylindraceous throat, .5-toothed. Style-branches with short 

 and obtixse or minutely apiculate conical tips. Akenes narrow, linear-oblong, terete, rather 

 thin-walled, smooth, evenly 8-15-nerved : pappus setulose or none. Shrubby or .suffruticose. 



92. ISOCARPHA. Involucre, receptacle, and dry bracts nearly of the preceding genus. 

 Corolla similar but small. Style-branches with subulate tips. Akenes 4-5-angled, small, 

 little compressed, destitute of pappus. Herbaceous. 



93. SPILANTHES. Some (exotic) species have no ray-flowers, and akenes not flat, with 

 pappus also wanting : these resemble Isocarpha. 



++ ++ Rays present, but in several genera occasionally wanting : involucre commonly her- 

 baceous or foliaceous, or partly so. 



== Receptacle higli, from conical to columnar or subulate, at least in fruit. (Here Gijm- 

 nolomia, as to two species, would be sought. ) 



a. Rays fertile, or not rarely wanting : style branches of the disk-flowers truncate and some- 

 times peuicillate at tip : akenes small : leaves opposite. 



93. SPILANTHES. Involucre of a few somewhat herbaceous loosely appres.sed liracts. 

 Bracts of the receptacle soft and cliaffN-, shorter than the flowers, more or less conduplicate 

 and emliracing the akenes, at length falling with them. Disk-corollas 4-5-toothed. Akenes 

 of the ray triquetrous or obcompressed ; those of the disk either moderately or much com- 

 pressed and with acute or nerve-like margins, sometimes ciliate-fimbriate. Pappus a 

 setiform awn from one or more of the angles, or none. 



b. Rays sterile (imperfectly styliferous in Echiimcea; otherwise completely neutral), soon 

 drooping, sometimes marcescent, the ligule with very short tube or none : style-branches 

 tipped with an acute or obtuse hispid appendage : leaves mostly alternate. 



94. ECHINACEA. Involucre imbricated in 2 or 3 or more series and squarrose ; its bracts 

 lanceolate. Disk at first only convex, becoming ovoid and the receptacle acutely conical. 

 Chaffy bracts of the latter firm and completely persistent, linear-lanceolate, carinate-concave, 

 acuminate into a rigid and spinescent cusp, surpassing the disk-flowers. Ligules elongated 

 and pendent in age, rose-colored or rose-purple, marcescent, usually imperfectly styliferous. 

 Disk-corollas cylindraceous, with 5 erect teeth and almost no proper tube (a ring upon 

 which the stamens are inserted). Akenes suberose-cartilaginous, acutely quadrangular, 

 somewhat obpyramidal, with a tliick coroniform pappus more or less extended into triangular 

 teeth at the angles ; the basal areola central. 



95. RUDBECKIA. Involucre looser, spreading, more foliaceous. Disk from hemispheri- 

 cal or globose to columnar, and receptacle from acutely conical to cylindrical and subulate; 

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

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

 Akenes 4-angled, prismatic, in some species quadrangular-compressed, or in one nearly 

 terete. Pappus a coriaceous or firni-scarious and often 4-toothed crown, sometimes deep 

 and cupuliform, sometimes obsolete, or none. 



5 



