134 COMMON CANADIAN WILD PLANTS. 



2. T. glau'eum, Nutt. Scape 1-2 feet high. Leaves 

 varying from entire to dentate or laciniate. Achenes long- 

 beaked. N.W. prairies. 



55. TARAX'ACUM, Haller. DANDELION. 



T. Offleina'le, Weber. (T. dens-leonis, Desf.) (COMMON 

 DANDELION.) Outer involucre reflexed. Leaves runcinate. 

 Fields everywhere. 



56. LACTU'CA, Tourn. LETTUCE. 



1. L. Canaden'sis, L. (WILD LETTUCE.) Heads numer- 

 ous, in a long and narrow naked panicle. Stem stout, 

 smooth, hollow, 4-9 feet high. Leaves mostly runcinate, 

 partly clasping, pale beneath ; the upper entire. Achenes 

 longer than their beaks. Borders of fields and thickets. 



2. L. seari'ola, L. (PRICKLY LETTUCE.) Stem below 

 sparingly bristly. Leaves vertical, spinulose-denticulate, 

 oblong or lanceolate, prickly on the midrib below. Heads 

 small, 6-12 flowered. Waste places. 



3. L. integTifo'lia, L. Stem 3-6 feet high; leaves all 

 undivided, entire or slightly toothed. Flowers pale yellow, 

 cream-colour, or purple. Dry soil. 



4. L. hiFSU'ta, Muhl. Leaves runcinate, the midrib 

 beneath often sparingly bristly-hairy. Flowers yellowish- 

 purple, rarely white. Dry soil. 



5T. nUJLGE'DIOI, Cass. FALSE OR BLUE LETTUCE. 

 M. leueophse'um, DC. (Lactuca leucophcea. Gray, in 

 Macoun's Catalogue.) Stem tall and very leafy. Heads in 

 a dense compound panicle. Borders of damp woods, and 

 along fences. 



58. SOX'CIHIS, L. SOW-THISTLE. 



1. S. OlePa'eeus, L. (COMMON SOW-THISTLE.) Stem- 

 leaves runcinate, slightly toothed with soft spiny teeth, 

 clasping ; the auricles acute. Manured soil about dwellings. 



2. S. asper, Vill. (SPINY- LEAVED S.) Leaves hardly 

 lobed, fringed with soft spines, clasping; the auricles 

 rounded. Achenes margined. Same localities as No. 1. 



