coMPOSiTJi:. 61 



•1— Eay-flowers, or rather their ovaries and akeues, iu more than one series, and with elon- 

 gated exserted deciduous ligules ; the akenes falling free, or with only the subtending 

 bract. {Schtzomeria of Mexico is of this section, but with fewer ray-flowers.) 



70. SILPHIUM. Heads large, many-flowered. Involucre of thickisli more or less folia- 

 ceous imbricated bracts; the innermost (next to the akenes) small and chaffy. Recejitacle 

 comparatively small, the central part bearing the sterile flowers somewhat turbinate iu age ; 

 its chaffy bracts linear, flat, or involute around the pedicilliform abortive ovaries. Corollas 

 of the ray with a long and spreading ligule on a very short tuhe ; of the disk cylindrical- 

 tubular, the teeth very short and thickisli. Sterile style entire, much elongated in anthesis, 

 hispidulous. Akenes very flat and hroad, imbricated in 2 or 3 series, completely free 

 from the suhtending bract and from those of adjacent male flowers, surrounded l)y a winged 

 margin which is produced more or less beyond the summit on each side into a callous tooth 

 or auricle ; pappus none or sometimes a pair of short rigid awns or teeth, with which the 

 wing is confluently united. 



•)— -1— Ray-flowers and akenes in a single series ; the latter with 2 or 3 bracts of sterile 

 flowers (paleiB of the receptacle) attached to their base on the inner side, which they 

 take with them, and commonly also the subtending iuvolucral bract, when they fall. 



■H- Heads conspicuously radiate ; the ligules plane and exserted, subsessile, yellow, oblong 

 or oval : receptacle flat : its Ijracts or chaff, or at least the outer, of rather firm texture and 

 more or less involving their sterile flowers or inane ovaries. 



71. BERLANDIERA. Heads broad, with 5 to 12 radiate fertile and many hermaphrodite- 

 sterile flowers. Involucre hemispherical or broader ; its liracts in about three series ; outer- 

 most smaller and more foliaceous; the succeeding larger and usually dilated-obovate; 

 innermost thinner, becoming membranaceous or chartaceous and reticulated in age. Disk- 

 corollas, style, &c. as in Silphium. Akene very flat or slightly meniscoidal, obovate, wing- 

 less, not toothed or notched at summit, carinately unicostate down the inner face, with 

 evanescent or obsolete pappus (sometimes two minute and caducous bristly teeth or awns), 

 at the back more or less coherent with the base of the subtending plane involucral bract, at 

 length falling away with it, the ventral face partly covered by the spatulate bracts of the 

 2 or 3 attached sterile flowers. Alternate-leaved perennials. 



73. CHRYSOGONUM. Heads of mostly 5 radiate fertile and rather numerous sterile 

 flowers. Involucre campanulate, double; outer of 5 loose and obovate or spatulate folia- 

 ceous bracts which surpass the disk ; inner of as many small oval firm-meml)ranaceous erect 

 bracts, each subtending a fertile flower. Chaffy bracts of the receptacle thin, linear, the 

 outer broader and partly enclosing as many sterile flowers. Ligules oblong : disk-corollas 

 cylindraceous, with 5 small spreading teeth. Akene obovate or oval, flat or slightly menis- 

 coidal, with acute but wingless margins, one-nerved on the convex back, carinately 1-2- 

 costate on inner face, crowned with a truncate or crenately emarginate semi-cupulate 

 pappus, i. e. the crown wanting on the inner side ; the involucral bract with which it falls 

 little larger than its back, and closely applied to but not cohering with it : adjacent sterile 

 bracts less persistent with the akene than in the following genus. Low and opposite-leaved 

 perennial. 



73. LINDHEIMERA. Heads of 4 or 5 radiate fertile and rather numerous sterile 

 flowers. Involucre double ; outer of 4 or 5 loose and foliaceous narrow lanceolate bracts ; 

 inner of as many larger ovate-oblong herbaceous bracts, becoming chartaceo-membranaceous, 

 subtending the fertile flowers. Receptacle small ; its inner bracts chaffy, narrowly linear 

 and nearly plane ; the outer more herbaceous, spatulate, and enclosing the filiform abortive 

 ovary, which forms a long pedicel to the subtended sterile flower. Ligules oval or oblong, 

 almost entire : disk-corollas funnelform. Akene obovate, flat, slightly meniscoidal, unicos- 

 tate on the middle of each face (dorsally not adnate to the much larger subtending bract), 

 surrounded by a cartilaginous entire wing, which is confluent at apex with tAvo triangular- 

 subulate rigid teeth or horns ; a similar but smaller and naked tooth projecting from the 

 summit of the ventral costa. Erect annual, with sessile leaves, the upper opposite. 



74. ENGELMANNIA. Heads of 8 to 10 conspicuously radiate and of many sterile flowers. 

 Involucre hemispherical, somewhat double ; the outer of about 10 rather linear mainly 

 foliaceous bracts in two series, i. e. the outermost smaller and wholly loose and foliaceous, 

 the succeeding similar but with ovate-dilated and appressed coriaceous base ; inner of firm- 



