134 COMMON CANADIAN WILD PLANTS. 



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

 varying from entire to dentate or laciniate. Aohenes long- 

 beaked. — N.W. prairies. 



SS. TARAX'ACIJIH, Haller. Dandelion. 

 T. Offlcina'le, Weber. (jT. dena-leonis, Desf.) (Commom 

 Dandelion.) Outer involucre reflexed. Leaves runcinate. 

 — Fields everywhere. 



56. I/ACTE'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. SCari'Ola, L. (Peicklt 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. integrifO'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. hirsu'ta, Muhl. Leaves runcinate, the midrib 

 beneath often sparingly bristly-hairy. Flowers yellowish- 

 purple, rarely white. — Dry soil. 



ST. MBLCE'MBM, Cass. False oe Blue Lettuce. 

 M. leucophse'um, DC. {Lactuca leucophcsa. Gray, in 

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

 oi dense compound panicle. — Borders of damp woods, and 

 along fences. 



58. SOK'CHVS, L. Sow-Thibtle. 



1. S. olera'ceus, 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. (Spint-leavbd S.) Leaves hardly 

 lobed, fringed with soft spines, clasping; the auricles 

 rounded. Aohenes margined. — Same localities as No. 1. 



