THISTLE FAMILY 911 



99. E. ochroleucus Nutt. Perennial, with a cespitosecaudex;stem 1-2 dm. 

 high, cinercH)Us-striu;()se; leaves narrowly linear, 3-7 cm. long, strigose and hispid- 

 ciliate below; heacls usually solitary; involucres about 5 cm. high, 10-12 mm. 

 broad; ligulcs 40-GO, ochroleucous or white. Gravelly hills: Ore. — Ida. 



100. £. peucephyllus A. Gray. Perennial, with a densely cespitosecaudex; 

 stems 1-2 dm. high, cinereous-strigose, erect; leaves filiform, cinereous, 2-5 cm. 

 long; heads usually solitary; involucres 4-5 mm. high, 8-10 mm. broad; bracts 

 linear, acute, hirsute; ligules 5-6 mm. long. E. filifolius Piper, not Nutt. Dry 

 hills: B.C.— Calif.— Ida.— Sask. Son.— Mont. My-Jl. 



101. E. pulvinatus Rydb. Pulvinate cespitose perennial, with a very thick 

 woody root and short caudex; leaves basal, densely clustered, linear, 1-2 cm. 

 long, about 1 mm. broad, silvery-strigose; peduncles naked or with a single 

 diminutive leaf, about 3 cm. high, silvery-strigose; involucres hemispheric, about 

 1 cm. broad; bracts linear, in 3 series, slightly thickened on the back, silvery- 

 strigose, acute; ligules white, 6-7 mm. long; achenes (not mature) flat, hirsute 

 on the margins; pappus of rather few scabrous bristles. Arid places: Utah. Jl. 



46. LEPTILON Raf, Horseweed, Canada Fleabane. 



Annual or biennial, caulescent herbs. Leaves alternate, narrow. Heads 

 small, paniculate. Involucres campanulate; bracts in 2-3 series; receptacle 

 naked. Ray-flowers few, pistillate, with short white or purplish ligules, not 

 exceeding the disk. Disk-flowers several, perfect, with usually 4-lobed corollas. 

 Anthers obtuse at the base. Stigmas flat, with short, obtuse appendages. 

 Achenes flattened, often pubescent. Pappus of many capillary brittle bristles 

 in one series. 



1. L. canadense (L.) Britton. Annual; stem erect, ,5-30 dm. high, hirsute 

 or glabrate; lower leaves spatulate or oblanceolate, petioled, 2-10 cm. long, hir- 

 sute or at least ciliate on the margins, incised to entire; upper stem-leaves linear, 

 entire, sessile; heads numerous in an elongate panicle; involucres 3-4 mm. high 

 and broad; ligules numerous, white. Erigeron canadensis L. Waste places and 

 dry soil: Lab. — Fla. — Calif. — B.C.; Mex., W. Ind., and adv.' or nat. in Eu. 

 Plain — Submont. Je-N. 



47. ESCHENBACHIA Moench. 



Annual or perennial caulescent herbs. Heads paniculate or corymbose. 

 Involucres campanulate or subcylindric; bracts narrow in 1-3 series. Marginal 

 flowers pistillate, more numerous than the hermaphrodite central ones; corolla 

 with a slender filiform tube, without any ligule; their styles truncate or toothed 

 at the apex. Achenes compressed. Pappus in a single series of soft capillary 

 bristles. [Coinjza Less., not L.] 



1. E. Coulteri (A. Gray) Rydb. Annual; stem erect, 3-6 dm. high, hirsute- 

 villous and viscid; lower leaves spatulate or oblanceolate, dentate or laciniate, 

 2-5 cm. long, hirsute and glandular-puberulent; upper leaves oblong or linear- 

 lanceolate; heads numerous in an elongated panicle; involucre about 3 mm. high 

 and broad; bracts linear-subulate, viscid-hirsute; flowers whitish ; pistillate flow- 

 ers numerous, with an entire corolla-tube ; hermaphrodite flowers 5-7. River 

 bottoms: Tex. — Colo. — Calif.; Mex. Son. 



48. BACCHARIS L. Groundsel Tree. 



Perennial caulescent herbs or shrubs, usually with glabrous^ resinous foliage. 

 Leaves alternate, often leathery, entire or toothed. Heads discoid, dioecious, 

 corjanbose or paniculate. Involucres campanulate; bracts imbricate in several 

 series, those of the pistillate heads often more numerous; receptacle flat, pitted, 

 naked. Corollas mostly yellow, those of the staminate plant tubular, those of 

 the pistillate heads filiform. Anthers entire and obtuse at the base. Pappus of 

 filiform bristles, those of the pistillate heads usually elongating in fruit, very 

 fine, those of the staminate heads shorter, scabrous and often tortuose. 



