/ 



TPIISTLE FAMILY 941 



3-nerved, the outer more or less keeled. Ray-flowers few, pistillate and fertile; 

 ligules yellow, short. Disk-flowers many, hermaphrodite and fertile; corollas 

 yellow. Achenes elongate-obpyramidal, glandular or hispidulous. Pappus of 

 a crowTi of 8 ovate or lanceolate squamellae. 



1. P. oppositifolia (Nutt.) Rydb. Stem 1-2 dm. high, branched below, 

 strigose-puberulent; leaves 1-5 cm. long, impressed-punctate and strigose-pubcru- 

 lent; involucres 5-7 mm. high and 7-10 mm. broad; ligules 3-4 mm. long; achenes 

 glandular. Bahia oppositifolia A. Gray. Alkaline soil and dry plains: N.D.— 

 Tex. — Aj-iz. — Mont. Plain — Submont. Je-S. 



92. AMAURIOPSIS Rydb. 



Glandular-pubescent annuals. Leaves alternate, twice or thrice ternately 

 divided. Heads radiate, in leafy corymbs. Involucre hemispheric; bracts 16-20, 

 herbaceous, in 3 series; receptacle flat, alveolate. Ray-flowers 16-20, pistillate, 

 fertile; hgules cuneate, 3-cleft. Disk-flowers hermaphrodite and fertile; corollas 

 yellow, Achenes elongate, narrowly obpyramidal, 4-angled, striate. Pappus 

 wanting. 



1. A. dissecta (A. Gray) Rydb. Stem 3-10 dm. high, puberulent or gla- 

 brate below, glandular above; leaves with oblong or Knear obtuse divisions, more 

 or less puberulent; involucres 6-7 mm, high, about 1 cm. broad, glandular-pu- 

 berulent; bracts oblong-oblanceolate to obovate-oblong, abruptly acummate. 

 Bahia chrysanthemoides A. Gray. Yillanova dissecta Rydb. Along streams: 

 N.M.— Wyo.— Ariz.; n Mex. Son.— Mont. Jl-S. 



93. PLATYSCHKURIA (A. Gray) Rydb. 



Perennial grayish puberulent herbs, woody at the base. Leaves alternate, 

 petioled, entire. Heads radiate, corymbose. Involucre hemispheric; bracts 

 herbaceous in 2 series, oblong; receptacle flat, glabrous. Ray-flowers pistillate 

 and fertile; ligules yellow, oblong, sUghtly 3-toothed. Disk-flowers fertile; 

 corollas glandular, yellow. Achenes elongate, 4-angled, tapering do^\-nward, 

 sparingly hairy on the angles. Pappus of 10-16 lanceolate squameUae, with the 

 distinct midrib extending beyond the apex. 



Stem scapiform or nearly so; leaves firm, oval to lancteolate. 1. P. integrifolia. 



Stem leafy; leaves thin, oblong. ^- -^- oblongijolxa. 



1. P. integrifolia (A. Gray) Rydb. Stem 1.5-4 dm. high, almost scapiform; 

 basal leaf-blades cinereous-puberulent, oval to lanceolate, 2-7 cm. long, 3-ribbed, 

 thick- upper stem-leaves much reduced, linear-lanceolate; involucres 8-10 mm. 

 high ' 12-20 mm. broad; ligules 8-10 mm. long; pappus-squamellae lanceolate, 

 erose 2 mm. long. Bahia integrifolia A. Gray. B, nudicaulis A. Gray. B. 

 desertorum M. E. Jones. Dry plains: Wyo.— Colo.— Utah. Son.— Submont. 



My~Je. 



2. P. oblongifolia (A. Gray) Rydb. Stem leafy, 2-3 dm. high, stngose- 

 puberulent: leaf-blades oblong or lanceolate, obtuse, 2-5 cm long, 3-ribbed; 

 involucres about 8 mm. high and 12 mm. vnde; pappus-squamell^ hnear-lanceo- 

 hite, entire, fully 4 mm. long. Bahia oblongifolia A. Gray. Arid regions: N.M. 



Colo.— se Utah— Ariz. Son. Jl-S. 



94. HtJLSEA T. & G. 



More or less fleshy villous or viscid perennials, biennials, or annuals. Leaves 

 alternate, sessile or with winged petioles. Heads radiate, large. Involucre 

 hpmisTjheric' bracts in 2 or 3 series, narrow; receptacle flat, alveolate-dentate 

 ^Mth minute horny teeth. Ray-flowers pistillate and fertUe; Ugul^^^ ^i^^^r^i^ 

 vellow or purpUsh. Disk-flowers fertile; coroUas yellow, glandulai 

 branches obtuse. Achenes Unear-cuneate, compressed, villous especiaUy on the 

 margins. Pappus of 4 hyaUne nerveless squamellae. 



1 H caxnosa Rvdb. Perennial, with a thick root and creeping subterranean 

 stems cespitose; ovefground stems 1.^3 dm high, very leafy throughout pubes- 

 ^^^ . ijrrfl 1.L .r\J{^^ 1p^.v^<. vftrv fleshv. hnear, smuately lobed, viscid-pubes- 



■viscid 



