924 CARDUACEAE 



clavate, 7-8 mm. long. Damp woods: B.C. Calif. Mont. Lake Superior. 

 Mont. Je-Au. 



59. MELAMPODIUM L. 



Annuals or perennial herbs or shrubs. Leaves opposite, often narrow, entire, 

 toothed or pinnatifid. Heads radiate. Involucres double, the outer of 4-5, 

 partially united flat bracts, the inner of a series of bracts, each embracing an 

 achene, and deciduous with it. Receptacle convex or conic. Ray-flowers in 

 one series, pistillate, white or yellow. Disk-flowers hermaphrodite, but sterile. 

 Anthers entire at the base. Achenes broadened upwards, somewhat incurved. 

 Pappus wanting. 



1. M. leucanthum T. & G. Perennial, with a taproot and short caudex; 

 stems several, branched below, 1-3 dm. high, cinereous-strigose ; leaves linear or 

 the lower oblanceolate, 3-5 cm. long, entire or sinuately lobed; involucres about 

 5 mm. high and fully 1 cm. broad, cinereous; ligules white, about 1 cm. long and 

 5 mm. wide. Dry plains: Tex. Colo. Ariz. Plain Submont. Mr-O. 



60. SILPHIUM L. ROSINWEED, COMPASS PLANT. 



Large perennial herbs, often with resinous sap. Leaves alternate. Heads 

 radiate. Involucres hemispheric or campanulate; bracts broad, in few series. 

 Receptacle flat, with numerous paleae. Ray-flowers pistillate, in 2 or 3 series, 

 fertile; ligules yellow, rarely white. Disk-flowers hermaphrodite but sterile; 

 corollas yellow. Anthers 2-toothed at the base or entire. Achenes flat and 

 broad, 2-winged, notched at the apex. Pappus wanting or of 2 small awns. 



1. S. integrifolium Michx. Stem 8-15 dm. high, rough-pubescent, 4- 

 angled; leaves mostly sessile, ovate to lanceolate, entire or dentate, 7-12 cm. 

 long, scabrous; involucre 1-1.5 cm. high; bracts triangular-ovate to lanceolate, 

 acute, or the inner obtuse; ligules 15-23, yellow, 2-3 cm. long. ROSINWEED 

 Prairies: Mich. Miss. Tex. Colo. Minn. Plain. Au-S. 



61. ENGELMANNIA T. & G. 



Perennial herbs, with alternate pinnatifid leaves. Heads radiate. Involucres 

 hemispheric, or campanulate; bracts of 2 or 3 series, the outer narrow, the inner 

 broad. Receptacle flat, chaffy. Ray-flowers 8-10, pistillate, fertile; ligules 

 yellow. Disk-flowers hermaphrodite, but sterile, partly embraced by the paleae. 

 Anthers 2-toothed at the base. Achenes flat, broader upwards, 1-ribbed on 

 each side. Pappus an irregular crown. 



1. E. pinnatifida T. & G. Stem 3-7 dm. high, hirsute or hispid; leaves 5-15 

 cm. long, pinnatifid, the upper sessile; outer bracts linear, the middle ones sub- 

 orbicular, with linear tips, and the inner oval or obovate, ciliate; ligules 8-10, 

 golden yellow, 1 cm. long. Plains and hillsides : La. Kans. Colo. Ariz. Son. 



62. BOLOPHYTA Nutt. 



Acaulescent cespitose herbs. Leaves all basal, crowded, entire. Heads 

 solitary, subsessile among the leaves, discoid. Involucres hemispheric; bracts 

 few, broad, in about 2 series, herbaceous. Marginal flowers pistillate, few, 

 without ligules; corollas truncate at the apex. Central flowers hermaphrodite 

 and sterile, their corollas tubular-f unnelf orm ; anthers entire at the base; styles 

 dilated, truncate and pubescent at the summit. Pappus a pair of oblong-lance- 

 olate membranous scales. 



1. B. alpina Nutt. Tufted, subacaulescent perennial, with a cespitose 

 caudex, 2-5 cm. high; leaves basal, crowded, silvery-canescent, spatulate-hnear,, 

 2-3 cm. long, entire; heads solitary, subsessile, 7-8 mm. wide. Parthenium 

 alpinum A. Gray. Among rocks: Wyo. Submont. 



63. PARTHENICE A. Gray. 



Annual herbs, with alternate leaves. Heads paniculate, discoid. Involucres 

 hemispheric, double, the outer of 5 somewhat herbaceous broad bracts, the inner 

 of 6-8 somewhat larger orbicular bracts more or less scarious, and subtending the 



