304 CICHORIACEAE 



9. LACTUCA L. 



Pappus bright white. 



Leaf-blades spiny-toothed and often spiny along the midrib beneath : corollas 

 yellow. 

 Involucres 6-i2-flowered : beak longer than the achene-body. 



1. L. Scar tola. 

 Involucres 12-20-flowered : beak shorter than the achene-body. 



2. L. sa^iUifolia. 

 Leaf-blades without spines on the margins or midrib. 



Achenes thin, the body prolonged in a slender beak. 

 Leaf-blades, at least some of them, pinnatifid. 



Leaves glabrous. 3. L. Canadensis. 



Leaves hirsute, at least on and about the midrib. 4. L. hirsnla. 

 Leaf-blades entire or merely toothed. 2. L. sagittifolia. 



Achenes thick, the bodj' beakless or with a mere thick neck. 

 Leaf-blades toothed : achene-body not narrowed into a neck. 



5. L. villosa. 

 Leaf-blades pinnatifid : achene-body narrowed into a neck. 



6. L. Floridana. 

 Pappus brown. 7. L. spicaia . 



1. Lactuca Scariola L. Prickly Lettuce. (Mau. p. 898; I. F. /. 

 3537-) In fields and waste places, Me. to S. Dak., N. J., Ga., Neb., Colo, 

 and Kans. Nat. from Eu. — Pennsylvania : North.\mpton ; Lancaster ; 

 Franklin ; Allegheny. 



2. Lactuca sagittifolia Ell. Arrow-leaved Lettuce. (Man. p. 

 89S ; I. F. /. 3S4S.) In dr}' open soil, N. B. and Ont. to Idaho, Ga. and 

 Kans. — Pennsylvania : Northampton ; L.-^ncaster ; Allegheny. 



3. Lactuca Canadensis L. Wild or Tall Lettuce. (Man. p. 898 ; 

 I. F. f. 3j3g.) In moist, open places, N. S. to the N. W. Terr., south to 

 Ga., Ala., La. and Ark. — Pennsylvania : Monroe ; Northampton ; 

 Bucks ; Luzerne ; Lancaster ; York. 



3a. L. Canadensis montana Britton. (Man. p. 89S. ) — Monroe; 

 Bucks ; Allegheny. 



4. Lactuca hirsuta Muhl. Hairy Wood-LETTuce. (Man. p. S9S ; 

 I. F. /. 3S40.) In dry soil, Me. to Ont, Minn., Ala. and Tex. — Pennsyl- 

 vania : Elk ; York. 



5. Lactuca villosa Jacq. Hairy- veined Blue Lettuce. (Man. p. 

 899; I. F./. 3J./3.) In thickets, N. Y. to 111., south to Fla., Ga. and Ky. 

 — Pennsylvania : Northampton ; Lancaster ; Franklin ; Alle- 

 gheny. 



6. Lactuca Floridana (L.) Gaertn. Florida LETTUCE. (Man. p. 899; 

 I. F. /. 3544.) In moist, open places, southern N. Y. and Pa. to 111., 

 Neb., Fla., La. and Kans. — Pennsylvania : Northampton ; Lancaster ; 

 Franklin ; Delaware. 



7. Lactuca spicata (Lam.) Hitchc. Tall Blue Lettuce. (Man. 

 p. 899; I. F. /. 334S-) In moist soil, Newf. to Man., south to N. C, 

 Tenn., Iowa and S. Dak. — Pennsylvania : Monroe ; Northamp- 

 ton ; Bucks ; Chester ; Lancaster ; Lebanon ; Franklin ; Erie ; 

 Allegheny. 



