180 Flora of the Palouse Region 



cous, glabrous or loosely pubescent, 10-25 cm - long: peduncles stout, erect, 

 usually glabrous or glabrate, except at tbe base of the involucre, 30-60 cm. 

 high: involucre hemispherical, 2-3.5 cm - high, glabrous or somewhat pub- 

 escent at base: bracts in 2-3 indistinct series, lanceolate or nearly ovate, 

 acuminate, the outer shorter: corollas pale yellow: akene pubescent, 10- 

 ribbed, 10-14 mm. long, attenuate into a stout nerved beak shorter than the 

 body: pappus white, copious, the slender bristles scabrous, longer than the 

 akene. Low ground, common and variable. 



298. SONCHUS. 



Leafy-stemmed mostly glabrous generally coarse herbs, with 

 milky juice: flowers yellow, in corymbose or paniculate heads: 

 bracts of the involucre imbricated, the outer shorter: receptacle 

 flat, naked: pappus of copious very fine and short capillary 

 bristles, which are not plumose: corollas all ligulate: akenes flat 

 or flatfish, truncate, not beaked. 



S. asper Vill. Annual, erect, 30-90 cm. high, somewhat glaucous, glab- 

 rous below, glandular above: lower leaves ovate or broadly spatulate, obtuse 

 or acute, rarely lobed, spinulose-dentate, the petioles margined; upper leaves 

 oblong or oval, sessile and clasping at base, acuminate: heads cymosely ar- 

 ranged: involucre cylindric-campanulate, about 1 cm. broad, glabrous: flow- 

 ers yellow: akenes flat, margined, 3-nerved on each side. Sparingly intro- 

 duced. 



299. LACTUCA. 



Leafy-stemmed herbs, with milky juice: flowers yellow or blue, 

 in paniculate few to many-flowered heads: bracts of the invol- 

 ucre in 2-few rows, the outer shorter: receptacle flat, naked: pap- 

 pus of copious very short and fine capillar}- bristles which are not 

 plumose: corollas all ligulate: akenes flat or Hattish, narrowed at 

 the summit or beaked. 



Leaves spiny: flowers yellow. L. scariola. 



Leaves not spiny: flowers violet. L. pclcheixa. 



L. SCariola L. Biennial, erect, 1-2 m. high, glabrous and somewhat 

 glaucous: leavesoblong or lanceolate, spiny on the margin and midrib, entire 

 or irregularly toothed or cleft, sessile and usually auriculate-clasping at base, 

 5-20 cm. long, the uppermost much reduced: heads in large loose panicles: 

 involucre narrowly cylindric, glabrous, 10-12 mm. loiu r , the outer bracts 

 much shorter than the inner ones: rays yellow: akenes flattened, narrowed 

 into a beak longer t^an the bod}-, as long as the bright white pappus. A 

 troublesome weed. 



L. pulchella DC. Perennial, erect, leafy, 30-90 cm. high, puberulent or 

 glabrate: leaves lanceolate, tapering at each end, acute or cuspidate, entire 

 or sinuately toothed or lobed, 5-15 cm. long; lower leaves petioled: heads 

 loosely panicled: involucre cylindric, glabrous,»i 2-14 mm. long, the outer 

 bracts successively shorter, all lanceolate, acute: flowers blue or violet: 

 akenes flat, not margined, 4 mm. long, very short beaked: pappus copious, 

 white. Banks of Snake River. A very troublesome weed in some sec- 

 tions. 



