> COMPOSITE FAMILY. 259 



78. CHONDRILLA. (Ancient name.) 



C. juncea, Linn. Branching herb, smooth above but bristly below, 

 l°-3'=, with wand-like stems ; root leaves runcinate ; stem leaves few and 

 small, linear ; small yellow heads scattered on the nearly leafless branches. 

 Weed E. Eu. @ 



79. L ACTUCA, LETTUCE. (Latin : milk, from the juice.) (f) 



* Akenes very flat, with a long filiform beak. Flowers mostly 



yellowish. 



L. Scarlola, Linn. Prickly Lettuce. Tall (3°-5°) and coarse weed 

 from Eu. ; stem sparsely prickly or bristly below, as also the mid-rib 

 on the under surface of the oblong spinulose leaves ; heads small and 

 yellow. 



L. satlva, Linn. Garden Lettuce. Supposed to be derived from the 

 above ; the broad and tender root leaves used for salad ; steni leaves, as 

 in the above species, standing edgewise, often exhibiting polarity. 



L. Canadensis, Linn. Wild Lettuce. Tall and very leafy (4°-9°), 

 smooth or very nearly so and glaucous ; leaves sinuate-pinnatifid, the 

 upper lanceolate and entire ; yellow heads in a long panicle. Common, 

 N. and S. 



L. Integrif6lia, Bigel. Rather lower and less leafy ; leaves undivided, 

 oblong-lanceolate, pointed, entire or denticulate ; heads yellow or 

 purplish. N. and S. 



L. hirsiita, Muhl. Stems generally reddish, 2°-4°, hirsute below, not 

 very leafy ; leaves runcinate-pinnatifid, more or less hirsute ; heads 

 purplish-yellow or rarely whitish. N. and S. 



* ♦ Akenes oblong and thickish, contracted into a short and thick neck; 



flowers mostly blue. 



L. acuminata, Gray. 3°-6° high, with ovate or lance-ovate barely 

 serrate leaves on winged petioles, blue flowers, and bright white pappus. 

 N. and R. 



L. Florid^na, Gaertn. Penn. W. and S.; like the last, but with all 

 the leaves or the lower ones lyrate or runcinate, uppermost partly clasp- 

 ing. 



L. leucopheea. Gray. Resembles Wild Lettuce, and with equally 

 variable lanceolate or oblong often irregularly pinnatifid leaves, very 

 compound panicle of pale blue or bluish- white flowers, and tawny pappus. 

 Low grounds. 



80. SONCHUS, SOW THISTLE. (Ancient Greek name.) Coarse 

 weeds, with soft-spiny-toothed runcinate-pinnatifid leaves; nat. from 

 Eu. (Lessons, Fig. 383.) 



* ® Heads pale yellow. 



S. oleraceus, Linn. In manured soil and damp waste places ; l°-6° 

 high, with acute auricles to the clasping base of the leaves, pale yellow 

 flowers, and akenes wrinkled transversely. 



S. dsper, Vill. Like the last, but the leaves less divided and more 

 spiny-toothed, the auricles of their clasping base rounded, and akenes 

 smooth with 3 nerves on each side. 



* * 21 Heads larger, bright yellow. 



S. arvensis, Linn.; ^-2° high from creeping rootstocks, with bristiy 

 peduncles and involucre. 



