324 THE COMPOSITE FAMILY. 



XXXIII. LETTUCE. LACTIICA. 



Aimual or perennial herbs, glabrous or with a few stiff bristles ; the stems 

 leafy, erect, and branched, with (in the British species) numerous small 

 heads of yellow flowers. Involucre narrow, of a few imbricated bracts, 

 containing very few florets. Achenes flattened, tapering into a slender beak, 

 with a pappus of numerous white and silky, simple hairs. 



A genus widely spread over southern Europe and central Asia, and among 

 the exotic species includes several species difi'enng from the Britisli ones in 

 their large blue flowers. It has the flattened aclienes of Sowthistle, from 

 which the only positive distinctive chai-acter is the beak of the achenes, but 

 the narrow involucres and few florets generally give it a different habit. 



Leaves thin, on long stalks, with a broad terminal lobe. Panicle slen- 

 der. Beak shorter than the achene itself 1. Wall Z. 



Leaves mostly sessile, rather stiif, often pricldy. Panicle rigid. Beak 

 as long as or longer than the aehene. 

 Panicle rather loose, oblong or s^jreading. Beak about the length 



of the achene 2. PricMy X. 



Panicle almost reduced to a long, clustered spike. Beak about twice 



the length of the achene 3. Willow L. 



Our garden Lettuces are luxuriant forms, produced by long cultivation of 

 one or perhaps two southern species, which have not been as yet satisfac- 

 torily identified, some botanists believing them to be cultivated varieties of 

 1:h.e pricJcly L. 



1. ^Vall Iiettuce. Iiactuca muralis, Fresen. 

 {Prenanthes, Eng. Bot. t. 457.) 



A glabrous, erect annual or biennial, about 2 feet high, with slender 

 branches, forming a loose, termmal panicle. Leaves few and thin, rather 

 large, with a broadly triangular, toothed or lobed, terminal segment, and a 

 fevv irregular smaller ones along the stalk ; the upper leaves sinall, narrow, 

 and entire or toothed. Flower-heads small, on slender pedicels. Involucres 

 about 5 lines long, of 5 equal, linear bracts, with 1, 2, or 3 very small outer 

 ones, containing is or 5 florets. Beak of the achenes much shorter than 

 the achene itself. 



In woods and shrubby places, in Europe and Eussian Asia, extending 

 far into the north, althouglt not an Arctic plant. Not uncommon in Eng- 

 land and Ireland, more rare in southern Scotland. Fl. summer. 



2. Prickly Lettuce. Iiactuca scariola, Linn. 

 (Eng. Bot. t. 268.) 

 An erect, stiff annual or biennial, 2, 3, or even 4 feet high, of a more or 

 less glaucous green, with short but spreading branches, and quite glabrous, 

 except a few stiff' bristles or small prickles on the edges or on the midrib of | 

 the leaves. Leaves more or less spreading, varying from lanceolate to 

 broadly oblong, either bordered only with small teeth, or with a few short 

 lobes or coarse teeth usually curved downwards, or deeply pimiatifid with 

 few narrow lobes ; the upper ones narrow, more entire, and clasping the 

 stem with pointed auricles. Flower-heads in a moi-e or less leafy panicle, 

 sometimes long and narrow, sometimes more branched and spreading. 

 Involucres 4 or 5 hues long, of a few imbricate bracts, the short, broad, 

 outer ones passing gradually into the inner, long, narrow ones. Florets 

 6 to 10 or 12, of a pale yellow. Achenes much flattened, obovate-oblong, 



