THISTLE FAMILY 999 



much reduced, lanceolate, sessile; cjTne corymbiform; heads cylindro-campanu- 

 late, about 1 cm. high; bracts linear; ligiiles few, light yellow, about 7 mm. long; 

 achenes glabrous. Wet places: Mont. — Ida. — Wash. — B.C. Je-Jl. 



95. S. pereziifolius Rvdb. Stem 6-8 dm. high, glabrous, striate, some- 

 what branched above; basal leaves 2-2.5 dm. long, thin and glabrous, oblong or 

 elliptic, with a short winged petiole, sinuately dentate, with small sharp sahent 

 teeth; lower stem-leaves similar, but sessile; the upper ones linear, with entire 

 margins; cyme rather narrow; heads cylindric-campanulate, about 1 cm. high; 

 bracts linear, tip})ed with black, much shorter than the disk; ligules fully 1 cm. 

 long; achenes glabrous. Swampy ground: Mont. Submont. Jl. 



96. S. lapathifolius Greene. Stem glabrous, about 3 dm. high; leaves 

 1-1.5 dm. long; lower leaves linear-oblanceolate, glabrous, denticulate, tapering 

 below into broadly winged petioles; upper leaves linear-lanceolate, half-clasping; 

 heads 5-10; involucres campanulate, 10^15 mm. high, with the peduncle gradually 

 thickened under the head; bracts lanceolate, thickened on the back, the calycu- 

 late ones few, linear-subulate, almost as long; ligules about 1 cm. long, narrow; 

 achenes glabrous. Mountains: Colo. — Wyo. Mont. — Subalp. Jl-Au. 



97. S. crassulus Gray. Stem 2-4 dm. high, glabrous; basal leaves 8-15 cm. 

 long; blades obovate or lanceolate, acutish or obtuse, dentate or denticulate, 

 tapering into a winged petiole; upper stem-leaves oblong, ovate, or lanceolate, 

 sessile and clasping at the base; heads corxinbose; involucre campamdate, 12-15 

 mm. high and 10-12 mm. broad; bracts oblong, acute, very thick and fleshy, the 

 inner with membranous margins, slightly shorter than the disk, the calyculate 

 ones linear-subulate, about one-third as long; ligules bright yellow, about 1 cm. 

 long; achenes glabrous. Subalpine meadows: (Black Hills) S.D. — N.M. — Utah 

 — Ida. Submont. — Alp. Je-Au. 



98. S. semiamplexicaulis Rydb. Stem 4-6 dm. high, glabrous; lower 

 leaves obovate, tapering into winged petioles, acute, the upper oblong, more or 

 less clasping by a slightly auricled base, acute or acuminate, all very thin, sinu- 

 ately dentate and often with salient teeth; heads few; disk 12-15 mm. high; invo- 

 lucres campanulate; bracts oblong, tipped with black, much shorter than the 

 disk; ligules narrow, about 8 mm. long; achenes glabrous. Wet meadows: Mont. 

 — Colo. — Utah — Ida. Submont. — Mont. Jl-Au. 



99. S. rapifolius Nutt. Stem 2-5 dm. high, terete or slightly obtuse- 

 angled; leaves rather thin, sharply dentate or incised; blades of the lower leaves 

 obovate or broadly oblanceolate, obtuse or acutish, 3-10 cm. long, tapering into 

 wing-margined and auricled petioles, half-clasping at the base; upper leaves sub- 

 sessile, oval, oblong, or lanceolate, clasping and auricled at the base; heads 

 numerous, panicled, 6-8 mm. high and about 5 mm. broad; bracts oblong, acute, 

 thick on the back, membranous-margined, about two-thirds as long as the brown- 

 ish yellow disk; ligules none; achenes glabrous. S. lactuciniis Greene. Rocky 

 wooded hillsides and mountains: Ida. — Colo. — S.D. (Black Hills). Submont. 

 Jl-Au. 



100. S. Scribneri Rydb. Stem stout, 2-3 dm. high, more or less villous; 

 basal leaves oval or oblanceolate, with somewhat winged petioles, 3-4 cm. long, 

 fleshy; stem-leaves linear or linear-lanceolate, the upper sessile; heads 5-16, 10-15 

 mm. high; involucre campanulate; bracts linear, slightly villous, long-attenuate; 

 ligules 12-15 mm. long; achenes glabrous. Wet places: Sask. — ]\Iont. Je-Jl. 



101. S. integerrimus Nutt. Stem 3-10 dm. high, striate, leafy, branched 

 above; basal leaves oblong-lanceolate, entire or sinuate-petioled, acute, some- 

 what fleshy; stem-leaves linear-lanceolate, sessile, sometimes auricled at the 

 base; heads numerous, 12 mm., or in fruit even 16 mm. high and 10-15 mm. broad; 

 involucres campanulate; bracts narrowly lanceolate, long-acuminate, thick and 

 fleshy, somewhat shorter than the disk; hgules duU yellow, about 1 cm. long; 

 achenes glabrous. Wet meadows: Minn. — Neb. — Colo. — Sask. Plain — Sub- 

 mont. Je-Au. 



102. S. Hookeri T. & G. Stem stout, arachnoid-villous when young, gla- 

 brate in age, simple, 2-3 dm. high; lower leaves 5-10 cm. long, more or less dis- 



