448 



COMPOSITAE. 



[Voi,. III. 



5-cleft limb. Anthers entire or emarginate at the base. Style-tips mostly truncate and ob- 

 tuse. Achenes quadrangular, linear or oblong. Pappus of several nerveless or costate 

 scales, rarely none. [Named for J. F. Bahi, Professor of Botany at Barcelona.] 



About 16 species, natives of western North America, Mexico and Chile. Besides the following, 

 some 10 others occur in the western parts of North America. 



i. Bahia oppositifolia Nutt. Bahia. 

 (Fig. 3967.) 



Trichophyllum oppositifolium Nutt. Gen. 2: 167. 



1818. 

 Bahia oppositifolia Nutt. ; T. & G. Fl. N. A. 2: 376. 



1842. 



Perennial, herbaceous;*stem densely cinereous, 

 much branched, 4 / -i2 / high, very leafy. Leaves 

 opposite, or the uppermost alternate, 



long, palmately 2-5-parted into linear, obtuse 

 or obtusish, entire segments, finely cinereous on 

 both sides; heads short-peduncled, 6 // ~9 // broad! 

 involucre campanulate, or becoming hemi- 

 spheric, its bracts oblong, obtuse, densely to- 

 mentose; rays 5-7, short; achenes linear-oblong, 

 glandular-pubescent; pappus of 4-8 spatulate 

 to lanceolate scales with thickened bases. 



On plains, Nebraska and Montana to New Mex- 

 ico. June-Sept. 



77. PICRADENIA Hook. Fl. Bor. Am. 1: 317. 1833. 

 [Actineixa Nutt. (1818), not Pers. (1807) nor Adinea Juss. (1803).] 

 Branched or scapose, villous-pubescent or glabrous, bitter and aromatic herbs, with al- 

 ternate or basal, often punctate leaves, and small or rather large, peduncled heads of both 

 tubular and radiate, yellow flowers, or rays rarely wanting. Involucre hemispheric, cam- 

 panulate or depressed, its bracts imbricated in 2-3 series, appressed, the outer ones some- 

 times united at the base. Receptacle convex or conic, naked. Ray-flowers pistillate and 

 fertile, the rays 3-toothed, 3-lobed Disk-flowers perfect, fertile, their corollas with 4-5- 

 toothed limbs. Anthers entire or minutely sagittate at the base. Style-branches truncate and 

 penicillate at the summit. Achenes turbinate, 5-10-ribbed or angled, villous or pubescent. 

 Pappus of 5-12 thin aristate acuminate or truncate scales. [Greek, bitter glands.] 



About 20 species, natives of western North America and Mexico. Besides the following, some 

 11 others occur in the western and southwestern parts of the United States. 

 Leaves entire; bracts of the involucre distinct to the base. 

 Stem leafy, branching; stem-leaves linear. 

 Stems tufted, simple, scapose; leaves basal. 



Leaves linear or narrowly spatulate, glabrous or slightly villous. 2. P. scaposa. 



Leaves spatulate, mostly densely silky- villous. 3. P. acaulis. 



Leaves 1-3-parted into filiform segments; outer bracts connate. 4. P. odorata. 



i. Picradenia linearifdlia (Hook.) 



Britton. Fine-leaved Picradenia. 



(Fig. 3968.) 



Hymenoxys linearifolia Hook. Icon. pi. 146. 1837. 

 Actinella linearifolia T. & G. Fl. N. A. 2: 383. 1842. 



Annual or perhaps biennial; stem usually dif- 

 fusely branched, finely hirsute, or glabrous, or 

 woolly at the base, slender, 6 / -i5 / high. Stem- 

 leaves narrowly linear, sessile, ^'-i^' long, % ,/ - 

 i // wide; basal leaves spatulate, often villous, 

 much broader, obtuse, narrowed into margined 

 petioles; heads numerous, slender-peduncled, 6"- 

 S // broad; involucre broadly campanulate, its 

 bracts oblong, obtuse, pubescent, distinct to the 

 base, imbricated in about 2 series; receptacle 

 conic; rays 6-10, oblong; achenes pubescent; pap- 

 pus of 5 or 6 ovate awned scales. 



In dr}- soil, Kansas to Louisiana, Texas and New 

 Mexico. May-Sept. 



1. P. linearifolia. 



