THISTLE FAMILY 941 



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

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

 j-ellow. Achenes elongate-obpyramidal, glandular or hispidulous. Pappus of 

 a cro-OTi of 8 ovate or lanceolate squameUae. 



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

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

 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. — Ariz. — 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; Ugules cuneate, 3-cleft. Disk-flowers hermaphrodite and fertile; corollas 

 yellow. Achenes elongate, narrowly obpjTamidal, 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 Unear obtuse divisions, more 

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

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

 Bahia chrysanthemoides A. Gray. Villanova 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 fiat, glabrous. Ray-flowers pistillate 

 and fertile; ligules j^ellow, oblong, shghtly 3-toothed. Disk-flowers fertile; 

 corollas glandular, yellow. Achenes elongate, 4-angled, tapering downward, 

 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 lancfeolate. 1. P. integrifolia. 



Stem leafy; leaves thin, oblong. 2. P. oblongifolia. 



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, Unear-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. — Suhmont. 

 My-Je. 



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

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

 involucres about 8 mm. high and 12 mm. wide; pappus-squamellae hnear-lanceo- 

 late, entire, fuUy 4 mm. long. Bahia oblongifolia A. Gray. Arid regions: N.M. 

 — sw 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 

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

 with minute horny teeth. Ray-flowers pistUlate and fertile; Ugules elongate, 

 j^eUow or purplish. Disk-flowers fertile; coroUas yellow, glandular- viscid. Style- 

 branches obtuse. Achenes linear-cuneate, compressed, viUous especiaUy on the 

 margins. Pappus of 4 hyaline nerveless squameUae. 



1. H. carnosa Rydb. Perennial, with a thick root and creeping subterranean 

 stems, cespitose; overground stems 1.5-3 dm. high, very leafy throughout, pubes- 

 cent, more or less viscid; leaves very fleshy, Unear, sinuately lobed, viscid-pubes- 



