DICOTYLEDONS. 233 



T. Taraxacum (L.) Karst. Dandelion. From a large, deep 

 root; leaves spatulate to elliptical, irregularly toothed or pinnatifid, 

 narrowed into a margined petiole ; scapes erect, 4-12 in. high ; heads 

 H-2 in. wide; involiicral bracts lanceolate to linear; flowers bright 

 yellow, very numerous ; achenes quite rough above, |-^ the length 

 of the filiform beak which is developed as the achenes mature ; pap- 

 pus a globose tuft of soft, white hairs. February-July. In lawns 

 and along roadsides; introduced. 



IV. SONCHUS. 



Annual or perennial ; leaves mostly toothed or pinnatifid, 

 prickly margined; heads in corymbs or panicles; bracts in 

 several series, the outer shorter ; receptacle naked ; flowers 

 yellow ; rays truncate, 5-toothed at the apex ; achenes oval to 

 oblong, compressed, ribbed, truncate at the apex ; pappus of 

 numerous soft, white hairs. 



1. S. OLERACEUS L. Sow Thistle. Auuual ; stem erect, 

 branched, smooth, 2-^^ ft. high; leaves spiny toothed, the lower 

 loiig-petioled, very irregularly cut or pinnatiiid, the upper clasping 

 l)y an auricled base ; involucre downy when young; achenes striate 

 and transversely wrinkled. May-August. In waste places on very 

 rich soil. 



2. 8. Asi'EH (L.) All. Spiny Sow^ Thistle. Annual; stem 

 erect, smooth, In'anched but little, '2-0 ft. high ; leaves undivided, 

 spatulate to oblanceolate, fringed with spiny teetli, the lower nar- 

 rowed into a petiole, the up})er clasping by an auricled base, the 

 auricles rounded ; heads numerous ; involucre glabrous ; achenes 

 flattened, margined, ^i-nerved on <^ach side, smooth. May-Septem- 

 ber. In waste places. 



y. LACTUCA. 



Annual, biennial or i)erennial; stems leafy; leaves entire 

 to i)innatifid ; heads panicled ; involucre cylindrical, bracts 

 unecpial, imbricated in 2 or more rows, the outer shorter; 

 receptacle naked ; flowers blue, yellow or white ; rays trun- 

 cate, 5-toothed at tlie apex; achenes compressed, ribbed, the 

 a])ex contracrted into a slender beak which is enlarged into a 

 disk bearing tlu' soft, hairy, white or tawny ]»appus. 



1. I.. Canadensis L. Wii.d I.ErrrcE. Hieiinial; stem erect, 

 sniofdli. hollow, branched ai>nve. :J-1() ft. high; leaves lanceolate to 



