1242 CARDUACEAE 
oval, suborbicular or rhombic ciliate bodies and involute curved or recurved acuminations : 
ray-flowers numerous ; ligules white, 2-2.5 cm. long: achenes oblong-oval, 15-18 mm. long, 
the wings prolonged above, the sinus U-shaped. 
In limestone soil, Texas. Summer. 
3. Silphium laciniàtum L. Stems stout, 1-3.5 m. tall, coarsely hispid. Leaves 
mainly basal ; blades 1-4 dm. long, the segments lanceolate to linear, entire or pinnatifid, 
the dilated bases of the petioles often pinnatifid : heads showy : involucres 2-2.5 cm. high ; 
bracts broadly lanceolate or ovate-lanceolate, 2.5-4 cm. long: ray-flowers numerous ; ligules 
yellow, 3-5.5 em. long: achenes oval to suborbicular, about 10 mm. long, narrowly winged, 
each with a shallow notch at the top. 
On prairies, Ohio to South Dakota, Alabama and Texas. Summer. COMPASS-PLANT. 
4. Silphium venósum Small. Stems scape-like, 8-12 dm. tall, glabrous or nearly so, 
glaucous. Leaves mainly basal; blades ovate to oblong, 1-3 dm. long, conspicuously red- 
veined, pinnately parted, the segments linear to linear-oblong, coarsely and irregularly 
toothed or incised ; petioles about 4 as long as the blades, dilated at the base: heads few, 
showy, corymbose: involucres campanulate, about 1 cm. high; bracts broadly oblong to 
orbicular-oval, rounded at the apex, ciliolate : ray-flowers several ; ligules yellow, 1-1.5 cm. 
long : achenes suborbicular, about 1 cm. long, the wings produced above, thus forming a 
narrow U-shaped sinus. 
In sand, southeastern Georgia. Spring and summer. 
5. Silphium compósitum Michx. Stems 1-2 m. tall, scape-like, more or less 
branched above. Leaves mainly basal and on the lower part of the stem ; blades mostly 
pedately parted, 1-3 dm. long, not conspicuously veined ; petioles longer than the mid- 
nerves: heads often numerous: involucres campanulate, about 1 cm. high; bracts ovate 
to broadly oblong, obtuse, ciliolate, dull without, lustrous within: ray-flowers several ; 
ligules bright yellow, 14-20 mm. long: achenes cuneate-obovate, 5-6 mm. broad. 
In dry soil, North Carolina and Tennessee to Georgia and Alabama, Summer and fall. 
6. Silphium ovatifdlium (T. & G.) Small. Stems 0.5-2 m. tall, glabrous or 
nearly so, branching above, rather scape-like. Leaves mainly basal; blades ovate to ob- 
long-ovate, 1-3 dm. long, mainly pinnately parted or pinnatifid, or irregularly and coarsely 
toothed and incised on the upper part of the stem ; petioles longer than the midnerves on 
the lower part of the stem : involucres campanulate, about 1 cm. high : bracts oblong, oval 
or oblong-ovate, rounded at the apex : ray-flowers several ; ligules yellow, 1-1.5 cm. long: 
achenes suborbicular, about 10 mm. broad. 
In sandy soil, southern Georgia and Florida. Spring and summer. 
7. Silphium renifórme Raf. Stems scape-like, 1-2 m. tall, glabrous or nearly so, 
corymbosely branched above. Leaves mostly basal; blades ovate to reniform, 1-3.5 dm. 
long, obtuse, coarsely dentate, deeply cordate at the base ; petioles longer than the blades 
on the lower part of the stem : involucres campanulate, 5-7 mm. high; bracts ovate or 
broadly oblong to narrowly oblong or oblong-spatulate, obtuse : ray-flowers Several ; ligules 
Hm 1-1.5 em. long: achenes suborbicular or orbicular-obovate, 7 mm. long; wings pro- 
onged enough to form a shallow sinus. 
In dry or stony soil, mountains of North Carolina. Summer. 
8. Silphium rumicifolium Small. Stems 4-8 dm. tall, reddish purple, scape-like, 
corymbose above. Leaves mainly basal; blades leathery, oblong to oblong-ovate, 1-1. 
long, rounded at the apex, repand-undulate, smooth, red-veined above, rather cuneate 
àt the base; petioles shorter than the blades, dilated and sheathing at the base: involucres 
hemispheric, fully 2 em. broad ; bracts varions, the outer suborbicular, broader than long, 
the inner oblong, rounded at apex: ray-flowers several; ligules yellow, 1.5-2 cm. long: 
achenes oblong-obovoid, 9-10 mm. long, narrowly winged and notched at the apex. 
In dry sterile soil, near Knoxville, Tennessee. Summer and fall. 
9. Silphium terebinthinàceum Jacq. Stems scape-like, 1-3 m. tall, branching nus 
the top. Leaves mainly basal; blades ovate, oblong-ovate or oblong, 1-6 dm. long, den- 
tate, with more or less prolonged teeth, cordate at the base: heads showy, relatively few : 
involucres broadly campanulate, 1-1.5 cm. high ; bracts various, the outer ovate or oval, 
the inner oblong, much broader than the outer, all obtuse and longer than broad mle 
flowers 15-25 ; ligules yellow, 2-3 cm. long: achenes cuneate, 8-9 mm. long, with sharp 
teeth at the top. 
In open grounds, Michigan to Iowa, Ohio, Georgia and Louisiana. Summer and fall. 
10. Silphium pinnatifidum Ell. Stems 0.5-3 m. tall, scape-like, often b 
branched above, pubescent. Leaves mainly basal; blades pinnatifid or pinnately parted, 
