866 COMPOSITAE (composite family) 



shaped base, the auricles acute ; involucre 

 downy when 'young ; achenes striate, also 

 loi'inkled transverseJy . — Waste places, chietiy 

 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, tlie auricles of the clasping base 

 rounded ; achenes margined, 3-nerved on each 

 side, smooth. — Waste places, roadsides, etc. 



T . i/ A'r^''" iv (Nat. from Eu.) Fig. 1018. 



Leaf X %. Achene x 1%. ^ '' 



100. LACTUCA [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, milk, in allusion to 

 the milky juice.) 



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

 the achene \\. 



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

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

 sagittate-clasping . 



* Heads small, (^-\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, spinulose-denticulate, tending to turn into a vertical position {i.e. with 

 one edge up); midrib iLsually 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. integrXta 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. SALiGXA L. Much more slender than the preceding species; stem 

 nearly or quite smooth ; leaves linear-oblong or narroio 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, 0. (^Selby, Kellerman). (Adv. 

 from Eu.) 



** Heads 'i2-20-flowered ; achenes oval to oblong-oval, blackish, narrow-mar- 

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



H- Leaves glabrous. 



3. L. canadensis L. (WildL., Horsk-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-pi nnatifid, the upper lanceolate and entire ; 

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

 panicle; flowers i)ale yellow. — Rich damp soil, borders of 

 fitdds or thickets, common. Fig. 101i>. Var. Montana Brit- 

 ton. Leaves all entire, rather narroioly ohlong-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. 

 lOl'j. L. canadensis. 4. L. integrifolia Bigel. Similar in stature," inflorescence. 



