592 COMPOSITAE 
1. Lactuca canadénsis L. Trumpet Fireweed. Fig. 6026. 
Lactuca canadensis L. Sp. Pl. 796. 1753. 
Lactuca elongata Muhl. ex. Willd. Sp. Pl. 3: 1525. 1804. 
Lactuca pase Rydb. Bull. Torrey Club 38: 23. 1911. 
Stout, weedy, simple-stemmed annual or _ 3-25 dm. high, glabrous or sometimes beri 
coarse ain hairs. Leaves entire, toothed, or deeply pinnately lobed, sagittate and often nar- 
rowed at base, 10-35 cm. long; panicle elongate , spreading, the peduncles —— heads 13- "2. 
flowered with yellow ligules ; fruiting Pe i usua — 10-15 mm. high, t phyllaries i in 4 or 
series ; achenes black, obovate, flat, transversely rugose with 1 prominent peeoe on eac = the 
beak about one-half as long ‘to equal the body of the sat di ndnc white, 7-10 mm. lon 
Fields and_woodland, introduced from the eastern United States, occurring ieee in adinder | in Wal- 
lowa County, Oregon, and in Siskiyou, Shasta, Plumas, and Amador Counties, California; also Idaho. Type 
locality: Canada. July y_Sept. 
A taxon quite variable as to leaf-shape and many named forms have been described. Both the entire-leaved 
and pinnatifid-leaved forms are found in the Pacific States. 
a ett ludoviciana (Nutt.) DC. Western Lettuce. Fig. 6027. 
Sonchus ludovici Nutt. Gen. 2: 125. 1818. 
Lactuca ludoviciana DC. oer 7: 141. 1838. 
Lactuca campestris anata Pittonia 4: 37. 1899. 
Biennial, t ms leafy the inflorescence, pahiculately bce attr above, 6-20 dm. high. 
Leaves a clasping yp uaaddienaeulats sinuate-lobed or pinnatifid with spinulose eee 
— setos sores id on the midrib, otherwise gla a direcahant: heads numerous re | 
pen pa tet hele pedirictos bes, er fruiting involucre 15-22 mm. high, cyclindric or pote 
evi ndric, a These: s, the phyllaries in 4 or 5 series and peg Mes shorter and broader ; ligules 
yellow ; achenes oval to obov te "i ms ttled with gray or i k, transversely rugose, 1-ribbe 
on each fac e, beak about equaling the “at dilated below ; white. 
SENS introduced sa ae visas arene Klickitat County, Washington, Wallowa County, Oregon; Shasta 
semety ig be ia, and vic of San ardino, southern California. Type locality: ‘‘Fort Mandan on the 
3. Lactuca virdsa L. Wild Lettuce. Fig. 6028. 
Lactuca virosa L. Sp. Pl. 795. 1753. 
Biennial, the stems stout, often 6-8 dm. high. Leaves ample, broadly obovate, 6-15 cm. long, 
strongly rae sharply dentate or sometimes. divided, glabrous, the midvein often prickly on the 
dorsal side ; Lees Borns often 30 cm. long and 15-20 cm. broa d; heads 6-12-flowered, yellow 
Grohe s 10-12 m. high; ac a hee i long, n acronis obovate, black, 4-5-ribbed P gored 
the thickened w sommes margin, cnuicasy spinulose a apex ; beak slender, ‘about equaling the 
of the pe ee ; pappus whi 
Seams lly on satan or yerey: shaded slopes; a European weed rather sparingly introduced in the San Francisco 
Bay region, " Californ . June 
4. Lactuca serridla L. Prickly Lettuce. Fig. 6029. 
Lactuca serriola L. Cent. Pl. 2: 29. 1756; Amoen. Acad. 4: 328. 1759. 
Lactuca scariola L. Sp. Pl. ed. 2.1119. 1763. 
Biennial, the stems leafy, ey soem branched above, 5-20 dm. high, glabrous throughout o 
prickly-hispid below, pale green or s colored. Leaves oblong or Ree cee Scions ae 
ing, lobed or pinnatifid, the tow 2 : i the upper much re : a5 ulose-hispid on t 
ag “ea 
midrib and margins, otherwise glabrous or more or less hispid; heads s in : usually large, 
seh panicle, 6-12- flow ate Scales ier sonal subcylindric or i Te conical, 12-16 mm. 
high, the phyllaries ee oiaste 4 i pigraegae in about 4 series, linear-lanceolate ; ieee obovate- 
oblong, about equaled by the slender beak; pappus white 
Be ids and waste places; a common weed in the Pacific States, ‘eo generously distributed in the United States. 
Native of Europe. Pe ns Ph ft. 
The plant with the leaves simple instead of lobed or divided has been recognized as a form (L. serriola var. 
integrata Gren. & Godr. Fl. France 2: 320. 1850). 
5. Lactuca saligna L. Willow Lettuce. Fig. 6030. 
Lactuca saligna L. Sp. Pl. 796. 1753. 
Annual, glabrous throughout, the stems usually several from a rather stout taproot, dec 
. high. v e 
, 3-7 Leaves pale green, narrowly linear-lanceolate, attenuate at a sagit- 
tate-clasping at base, en sometimes thed or f sn to : 8-10-flowered, yellow, in 
rrow spicate panicles with short pe cedis branches volucres narrowly cylindric, 1 se 
long ; achenes light brown, 3 mm. long, oblo Sie Caned os rather abruptly attenuate at a 
ribs 5-7 on each, a ‘spiculate near the apex, the beak slender, 5-6 mm. long; pappus- eae 
et — as long s the beak. 
Ae Aue wee ig has become well established in many places throughout California and has also been 
found in Dour and Marion Counties, Oregon; also eastward to the Atlantic seaboard. Type locality: Europe. 
6. Lactuca biénnis (Moench) Fernald. Tall Blue Lettuce. Fig. 6031. 
Sonchus biennis Moench, Meth. 545. 1794. 
Sonchus racemosus Lam. Encycl. 3: 400. 1789. Not Lact osa Willd. 1804. 
