276 



CICHORIACEAE. 



[Vol. III. 



g. Lactuca spicata (Lam.) Hitchc. 

 Tall Blue Lettuce. (Fig. 3545.) 



Sonchus spicatus Lam. Encycl. 3: 401. 1789. 

 Mulgediutn leucophaeum DC. Prodr. 7: 250. 



1838. 

 Lactuca leucophaea A. Gray, Proc. Am. Acad. 



19: 73. 1883. Not Sibth. 1840. 



Annual or biennial; stem usually stout, 

 glabrous, 3-i2 high, leafy up to the 

 large, rather dense panicle. Leaves deeply 

 pinnatifid or lobcd, sharply dentate with 

 mucronate-pointed teeth, sessile, or the 

 lower narrowed into margined petioles, 

 glabrous on both sides, or pubescent on the 



veins beneath, 



5'-"' 



long, 2 / -6 / wide; 



heads very numerous, about 1" broad; 

 peduncles minutely scaly; rays blue; 

 achenes oblong, compressed, narrowed 

 above into a short neck; pappus brown. 



In moist soil, Newfoundland to Manitoba, 

 south to North Carolina, Tennessee and Iowa. 

 Ascends to 2oco ft. in North Carolina. July-Oct. 



Lactuca spicata integrifolia (A. Gray) Britton, 



Mem. Torr. Club, 5: 350. 1894. 

 Lactuca leucophaea var. integrifolia A. Gray, 

 Syn. Fl. 1: Part 2, 444. 1884. 

 Leaves oblong, sharply denticulate, undivided, or some of the lower on 

 Carolina to Michigan. 



es pinnatifid. North 



16. LYGODESMIA D. Don, Edinb. Phil. Journ. 6: 311. 1829. 

 Perennial or annual glabrous rigid branching herbs, with linear leaves, or the basal and 

 lower ones sometimes broader and pinnatifid, those of the stem very narrow and entire or 

 reduced to linear scales, and middle-sized 3-12 flowered heads of pink or purple flowers, 

 solitary and erect at the ends of the stem and branches, or sometimes racemose. Involucre 

 cvlindric, its principal bracts 5-8, linear, scarious-margined, equal, slightly united at the 

 base, with several very short outer ones. Receptacle flat, naked. Rays truncate and 

 5-toothed at the apex. Anthers sagittate at the base. Style-branches slender. Achenes lin- 

 ear, smooth or striate. Pappus of copious somewhat unequal simple bristles. [Greek, twig- 

 bundle, from the numerous branches.] 



About 6 species, natives of western and southern North America. 

 Heads solitary at the ends of the branches; leaves linear or subulate. 

 Heads racemose along the branches; leaves elongated-linear. 



1. L.juncea. 



2. L. rostrata. 



i. Lygodesmia juncea (Pursh) 

 D. Don. Rush-like Lygodesmia. 



(Fig- 3546.) 

 Prenanthes juncea Pursh, Fl. Am. Sept. 498. 



1814. 

 Lygodesmia juncea D. Don, Fdinb. Phil. 



Journ. 6: 311. 1829. 



Perennial by a thick woody root; stems 

 stiff, striate, much branched, 8 / -i8 / high, 

 the branches erect. Lower leaves linear- 

 lanceolate, rigid, entire, acute, or acumi- 

 nate, Yz'-i' long, % ,r -\%f f wide, the 

 upper similar but smaller, or reduced to 

 subulate scales; heads & f -% ,f broad, 

 mostly 5-flowered, solitary at the ends of 

 the branches; involucre 6 // -8 // high; 

 achenes narrowly columnar or slightly 

 tapering, truncate at the summit, about 

 8-nerved or ribbed, 2> // ~3^ // long; pap- 

 pus light brown. 



Plains, Minnesota to Montana, Missouri, 

 Nebraska and New Mexico. Often infested 

 by a globose gall 2" -5" in diameter. June- 

 Aug. 



