GENUS 16, CHICORY FAMILY. 317 
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Annual, with fibrous roots; stem leafy be- y,) 
low, nearly simple, 1°-10° high. Basal and \ 
lower leaves petioled, lyrate-pinnatifid, 4’-10’ 
long, the terminal segment commonly large 
and triangular, the margins denticulate with 
mucronate or scarcely spiny teeth; upper leaves 
pinnatifid, clasping by an auricled or sagittate 
base, the auricles acute or acuminate; upper- 
most leaves often lanceolate and entire; heads 
several or numerous, pale yellow, 9-15” 
broad; involucre glabrous, 6”-8” high; achenes 
flat, longitudinally ribbed and transversely 
rugose. 
2. Sonchus olerdceus L. Annual Sow- 
Thistle. Hare’s Lettuce. Fig. 4066. 
Sonchus oleraceus L. Sp. Pl. 794. 1753. 
In fields and waste places, a common weed in 
most cultivated parts of the globe except the ex- 
treme north. Also in Central and South America. 
Naturalized from Europe. MHare’s-colewort or 
-thistle. Milk-weed. Milk-thistle. Milky tassel. j 
Swinies. The leaves used as a salad and as a pot herb. May-—Nov. 
<p,< 3. Sonchus asper (L.) Hill. Spiny or Sharp- 
fringed Sow-Thistle. Fig. 4067. 
Sonchus oleraceus var. asper L. Sp. Pl. 794. 1753. 
Sonchus asper Hill, Herb, Brit. 47. 1769. 
Annual, similar to the preceding species; leaves 
undivided, lobed or sometimes pinnatifid, spinulose- 
dentate to spinulose-denticulate, the lower and basal 
ones obovate or spatulate, petioled, the upper oblong 
or lanceolate, clasping by an auricled base, the 
auricles rounded; heads several or numerous, 1’ 
broad or less; flowers pale yellow; involucre gla- 
brous, about 6” high; achenes flat, longitudinally 
ribbed. 
In waste places throughout most of our area and in 
tropical and South America. Widely distributed as a 
weed in nearly all cultivated parts of the earth. Nat- 
uralized from Europe. May-—Nov. 
17. LACTUCA [Tourn.] L. Sp. Pl. 795. 1753. 
Tall leafy herbs, with small panicled heads of yellow, white, pink, or blue flowers, and 
alternate leaves. Involucre cylindric, its bracts imbricated in several series, the outer shorter, 
or of I or 2 series of principal nearly equal inner bracts, and several rows of short outer ones. 
Receptacle flat, naked. Rays truncate and 5-toothed at the summit. Anthers sagittate at 
the base. Style-branches mostly slender. Achenes oval, oblong or linear, flat, 3-5-ribbed 
on each face, narrowed above or tipped by a filiform beak, which is somewhat expanded 
at the summit into a small disk bearing the copious soft capillary white or brown pappus- 
bristles. [The Ancient Latin name, from Jac, milk, referring to the milky juice.] 
About 100 species, natives of the northern hemisphere. Type species: Lactuca sativa L. 
A. Achenes filiform-beaked; rays mainly yellow. 
Introduced European species; heads few-flowered. 
Panicle widely branching ; achene about as long as its beak. 1. L. virosa. 
Panicle-branches nearly erect ; achene shorter than its beak. 2. L. saligna. 
Native species; heads several- to many-flowered. 
Leaves, or their lobes, spinulose-denticulate; stem leafy below. 3. L. ludoviciana. 
Leaves entire to pinnatifid, the teeth not spinulose; stem leafy to the inflorescence. 
Leaves hirsute or bristly on the veins beneath. 
Plant hirsute below; leaves pinnatifid or the upper entire. 4. L. hirsuta. 
Plant hirsute up to the inflorescence; leaves merely dentate or denticulate. 
5. L. Steelei. 
