8«6 



COMPOSITAE ^COMPOSITE FAMILY) 



lOlS. S. asper. 

 Leaf X Yq. Achene x 1%. 



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. AspEK (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 eacli 

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

 (Nat. from Eu.) Pig. 1018. 



100. LACTtrCA [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 heals;, wliich 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 millcy juice.) 



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

 the achene 1|. 



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

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

 sagittate-clasping. 



* Heads small, 6-12-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 

 pinnatifld, spinulose-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 0., Mo., and Ky., chiefly westw., 

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



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

 only the lowest pinnatifld ; midrib prickly-setose or rarely smoothish. (i. 

 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. salIgna L. Much more slender than the preceding species; stem 

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

 natifld (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.XSelby, 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. 



H- Leaves glabrous. 



3. L. canadensis L. (Wild L., Horse-weed.) Mostly tall (1-3.2 m. high), 

 Tery 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. Fio. 1019. Var. montXna Brit- 

 ton. Leaves all entire, rather nairowly 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. 

 /ai9. L. canadensis. 4. L. integrifblia Bigel. Similar in stature, inflorescence, 



