Family ASTERACEA 199 
5. Taraxacum (Leontodon). 896. 
Outer bracts reflexed, not glaucous; heads 3-5 cm. broad; achenes 
brownish green. 1. T. taraxacum. 
Bracts spreading or ascending, glaucous; heads not over 2.5 cm. 
broad; achenes red. 2. T. erythrospermum. 
1. Taraxacum taraxacum (L.) Karst. Common Dandelion. 
A common weed all over the state, especially in lawns. Crete; Lin- 
coln; Minden; Red Cloud; Wahoo; Weeping Water. 
2. Taraxacum erythrospermum Andrz. Red-seeded Dandelion. 
More recently introduced, but common in many places. Hastings; 
Lincoln; Minden; Plainview; Red Cloud; St. Paul. 
6. Sonchus. 896. 
Leaves with acute auricles; achenes transversely wrinkled. 
1. S. oleraceus. 
Leaves with rounded auricles; achenes not transversely wrinkled. 
2. S. asper. 
1. Sonchus oleraceus L. Milk-thistle. 
Lexington; Lincoln; Pine Ridge. ; 
2. Sonchus asper (L.) All. Sow-thistle. 
A common weed throughout the state. Central City; Hastings; Hat 
Creek basin; Kearney; Lincoln; Nebraska City; Weeping Water. 
7. Lactuca. 897. 
Flowers yellow; beaks of the achenes as long as the body. 
Margins of the leaves, and often also the midribs, spiny. 
Heads 6—12-flowered, involucre 8-12 mm. high; achene gradually 
tapering to the beak. 1. L. virosa. 
Heads 12-—20-flowered, involucre 10-20 mm. high; achene abruptly 
narrowed to the beak. 2. L. ludoviciana. 
Margins of the leaves not spiny. 3. L. canadensis. 
ie ge blue or violet; achenes beakless or beak shorter than the 
ody. 
Achenes flat; involucre 15-20 mm. high. 4. L. pulchella. 
Achenes thicker, slightly compressed; involucre 10-12 mm. high. 
Achenes not beaked; leaves not pinnatifid. 5. L. villosa. 
Achenes short beaked; leaves pinnatifid. 6. L. floridana. 
1. Lactuca virosa L. Prickly Lettuce, Horse-thistle. 
A common weed in the eastern part of the state. Minden; Nebraska 
City; Red Cloud; Republican City. 
2. Lactuca ludoviciana (Nutt.) DC. Western Wild Lettuce. 
A common weed all over the state. Banner county; Cherry county; 
Franklin; Grand Island; Minden; Mullen; Nebraska City; Pishel- 
ville; Plummer Ford; Weeping Water. 
3. Lactuca canadensis L. Wild Lettuce. 
A common weed throughout the state. Cherry county; Long Pine; 
Nebraska City; Pishelville; Plummer Ford; Sioux county; St. Paul. 
4, Lactuca pulchella (Pursh) DC. Blue Lettuce. 
Throughout the state. Cherry county; Brown county; Lincoln; Mul- 
len; Nebraska City; Niobrara; Sioux county; Weeping Water. 
5. Lactuca villosa Jaca. 
Crawford; Lincoln; Nebraska City; Saltillo. 
