CARDUACEAE 1245 



bracts lanceolate to ovate, acute, ciliate : ray-flowers several, ligules yellow, 3-3.5 cm. 

 long : achenes broadly obovate or orbicular-obovate, 7-10 mm. long. 

 On plains or prairies, Arkansas to Louisiana and Texas. Summer and fall. 



25. Silphium gracile A. Gray. Stems 3-9 dm. tall, shaggy-hispid, sparingly corym- 

 bose above. Leaves opposite ; blades oblong-lanceolate, ovate-lanceolate or elliptic, 5-30 

 cm. long, acute at both ends or slightly acuminate, remotely dentate-serrate, those on the 

 lower part of the stem with petioles \ as long as the blades, those on the upper part of the 

 stem sessile or nearly so : involucres about 1 cm. high ; bracts inconspicuously pubescent, 

 ciliolate, oblong-lanceolate to ovate and oval -spa tulate, obtuse, or the outer acutish : achenes 

 orbicular-oval, 11-12 mm. long, very broadly winged, terminating above in 2 short teeth. 



In rocky soil or on prairies, Alabama to Texas. Summer. 



26. Silphium Mohrii Small. Stems 6-12 dm. tall, simple below, usually branched 

 above, shaggy-hispid, stout. Leaves alternate ; blades ovate-lanceolate to narrowly ovate, 

 5-14 cm. long, acuminate, remotely serrate with prominent teeth except near the base : 

 heads showy, but relatively few : involucres campanulate, about 1 cm. high ; bracts lan- 

 ceolate to ovate-lanceolate, acute or slightly acuminate, densely hispid : ray-flowers several ; 

 ligules yellow, 10-14 mm. long : achenes obovate, more or less constricted at both ends, 

 about 6 mm. long, surmounted by 2 acutish teeth. 



In dry soil, Tennessee and Alabama. Summer and fall. 



72. CHRYSOGONUM L. 



Perennial caulescent pubescent herbs. Leaves opposite : blades broad, toothed, pet- 

 ioled. Heads radiate, peduncled. Involucres hemispheric, double : an outer of 5 folia- 

 ceous bracts broadest above the middle ; an inner of firmer bracts, each subtending a ray- 

 flower. Ray-flowers pistillate, with broad yellow toothed ligules. Disk-flowers perfect, 

 not fruit-producing, each partly embraced by a bractlet. Anthers nearly entire at the base. 

 Achenes flattened, with acute margins, 1-ribbed on the back, 1-2-ridged on the inner face, 

 adnate to the subtending bract. Pappus a half cup-shaped crown. 



1. Chrysogonum Virginianum L. Stems becoming 1-3 dm. tall, hirsute, often 

 branching. Leaf-blades oblong, ovate or oval, 2-5 cm. long, obtuse, serrate or crenate, 

 the teeth more or less mucronate ; petioles about as long as the blades or longer : pedun- 

 cles about as long as the subtending bracts : heads conspicuous, few : involucres hirsute ; 

 outer bracts oblong-spatulate, 7-9 mm. long, the inner firmer, obovate, 4-5 mm. long, cilio- 

 late : ray -flowers about 5 ; ligules bright yellow, oval or orbicular-oval, about 1 cm. long : 

 achenes 4-4.5 mm. long. 



In sandy soil, Pennsylvania to Florida. Spring and summer. 



73. BERLANDIERA DC. 



Perennial pubescent caulescent or rarely scapose herbs. Leaves alternate, sometimes 

 basal : blades toothed or pinnatifid. Heads radiate, conspicuous, solitary or corymbose. 

 Involucres hemispheric or depressed, many -flowered : bracts in about 3 series, the inner 

 becoming thin, reticulated. Receptacle flat or nearly so, chaffy. Ray-flowers 5-12, pis- 

 tillate, fruit-producing : ligules yellow. Disk-flowers perfect, not fruit-producing. Anthers 

 entire or minutely 2-toothed at the base. Stigmas of the disk-flowers united. Achenes 

 flat, broadened upward, wingless, 1-ribbed within, more or less adnate to the adjacent 

 bracts of the involucre. Pappus obsolete, early deciduous or of 2 caducous awns. 



Leaf-blades merely toothed or slightly pinnatifid near the base. 

 Plants with stems leafy to near the inflorescence. 

 Stems tomentose or hirsute, or somewhat villous. 



Upper part of the stem and peduncles villous or villous-tomentose. 1. B. Texana. 



Upper part of the stem and peduncles hirsute with purple hairs. 2. B. betonicifolia. 



Steins closely woolly. 



Stem-leaves few, pubescent beneath, like the stem, with gray wool : species 



of the eastern Gulf region. 3. B. pumila, 



Stem-leaves numerous, pubescent beneath, like the stem, with white wool : 



species of the western Gulf region. 4. B. dealbata. 



Plants with scapes. . 5. B. humilis. 



Leaf-blades pinnatifid throughout. 



Stems hispidulous : Floridian species. 6. B. subacaulis. 



Stems tomentose : Texan species. 7. B. lyrata. 



1. Berlandiera Texana DC. Stems 6-12 dm. tall, villous or villous-tomentose, espe 

 cially above, corymbose above. Leaf-blades ovate-oblong to triangular-lanceolate or lanceo- 



