866 COMPOSITAE (COMPOSITE FAMILY) 



shaped base, the auricles acute ; involucre 

 downy when young ; achenes striate, also 

 wrinkled transversely. Waste places, chiefly 

 in manured soil and around dwellings. (Nat. 

 from Eu.) FIG. 1017. 



3. S. ASPER (L.) Hill. (SPINY-LEAVED S.) 

 Stem-leaves less divided and more spiny- 

 toothed, the auricles of the clasping base 

 rounded ; achenes margined, 3-nerved on each 

 side, smooth. Waste places, roadsides, etc. 

 Le .fxi AcZeW (Nat. from Eu.) Fio. 1018. 



100. LACTtTCA [Tourn.] L. LETTUCE 



Heads several-many-flowered. Involucre cylindrical or in fruit conical ; 

 bracts imbricated in 2 or more sets of unequal lengths. Achenes contracted 

 into a beak, which is dilated at the apex, bearing a copious and fugacious very 

 soft capillary pappus, its bristles falling separately. Leafy-stemmed herbs, 

 with panicled heads ; flowers of variable color, produced in summer and autumn. 

 (The ancient name of the Lettuce, L. sativa L. ; from lac, inilk, in allusion to 

 the milky juice.) 



N. B. In this genus, the figures of the fruiting heads are on a scale of f , of 

 the achene 1. 



1. SCARlOLA DC. Achenes very flat, orbicular to oblong, with a distinct 

 soft filiform beak; pappus white; biennial or annual; cauline leaves 

 sagittate-clasping. 



* Heads small, 6-]2-flowered ; achenes from linear-oblong to obovate-oblong, 



several-nerved, about equaling the beak ; introduced species. 



1. L. SCARIOLA L. (PRICKLY L.) Stem below sparsely prickly-bristly ; leaves 

 pinnatifid, sjrinulose-denticulate, tending to turn into a vertical position (i.e. with 

 one edge up) ; midrib usually setose beneath ; panicle loose, with widely spread- 

 ing branches ; flowers pale yellow, sometimes turning bluish in fading or drying. 

 Roadsides, railway ballast, etc., s. N. E. to O., Mo., and Ky., chiefly westw., 

 but even there less common than the following variety. (Adv. from Eu.) 



Var. INTEGRA.TA Gren. & Godr. Leaves oblong, denticulate, none of them or 

 only the lowest pinnatifid ; midrib prickly-setose or rarely smoothish. (L. 

 virosa of Am. auth., not L.) Waste grounds and roadsides, across the conti- 

 nent ; westw. an abundant and pernicious weed. (Nat. from Eu.) 



2. L. SALfGNA L. Much more slender than the preceding species ; stem 

 nearly or quite smooth ; leaves linear-oblong or narrow and runcinately pin- 

 natifid (the winged rhachis only 3-5 mm. wide), the margin sparingly toothed, 

 not regularly or conspicuously denticulate; heads short-pediceled, in virgate 

 somewhat fastigiate panicles. Waste ground, O.(Selby, Kellerman}. (Adv. 

 from Eu.) 



* * Heads 12-20-flowered ; achenes oval to oblong-oval, blackish, narrow-mar- 



gined, about equaling the beak, l-nerved on each face. 



i- Leaves glabrous. 



3. L. canadSnsisL. (WILD L., HORSE-WEED.) Mostly tall (1-3.2 m. high), 

 very leafy, glabrous or nearly so, glaucous ; leaves 1.5-3 dm. long, pale beneath, 



mostly sinuate-pinnatifld, the upper lanceolate and entire ; 

 heads 1-1.5 cm. long, numerous, in an elongated usually open 

 panicle; flowers pale yellow. Rich damp soil, borders of 

 fields or thickets, common. FIG. 1019. Var. MONTANA Brit- 

 ton. Leaves all entire, rather narrowly oblong-lanceolate. 

 Shores, clearings, and rocky uplands, N. S. to Ont. and O. 

 A similar state is often developed when the main axis is 

 injured as by mowing. 

 1019. L. canadensis. 4. L. integrifblia Bigel. Similar in stature, inflorescence, 



