FLOWERING PLANTS AND FERNS OF ARIZONA 1029 



2. Lactuca serriola L., Cent, PL 2: 29. 1756; Amoen. Acad. 4: 



328. 1756. 



Lactuca scariol a L.,Sp. PL ed. 2, 1119. 1763. 



Coconino, Yavapai, Maricopa, Pinal, and Cochise Counties, 1,000 

 to 7,000 feet, May to September. Abundant in southern Canada 

 and the United States; naturalized from Europe. 



Prickly lettuce, a common weed of roadsides and waste ground. 

 Two forms occur commonly — the typical form, with pinnatifid leaves, 

 and f. integrifolia Bogenhard (L. scariola var. integrata Gren. and 

 Godr.), with unlobed leaves. 



3. Lactuca graminifolia Miehx., Fl. Bor. Amer. 2: 85. 1803. 

 Apache, Coconino, Graham, Cochise, Santa Cruz, and Pima 



Counties, 5,000 to 7,000 feet, May to September. South Carolina 

 to Florida, west to Arizona. 



4. Lactuca ludoviciana (Nutt.) DC, Prodr. 7: 141. 1838. 



Sonchus ludovicianus Nutt., Gen. PL 2: 125. 1818. 



Fort Verde, Yavapai County (MacDougal 515), Tonto Basin, Gila 

 County (Tourney 617), 3,000 to 5,000 feet, July and August. Minne- 

 sota to Missouri, west to Colorado, Texas, and central Arizona. 



This species has not previously been recorded from Arizona. 



140. LYGODESMIA 



Annual or perennial herbs, essentially glabrous or merely puberu- 

 lent, sometimes spinescent; leaves entire or toothed; heads very small 

 to large, the corollas pink or rosy; involucre slender, of few equal 

 phyllaries and a calyculus; achenes subcylindric or linear-prismatic, 

 few-ribbed, not beaked; pappus of numerous capillary bristles, stiffisli 

 or soft. 



Key to the species 



1. Branches spinescent, rigid, divaricate; stems with tufts of brown wool at 

 base: lower leaves linear, entire, about 3 cm. long or less, the upper ones 



reduced to scales 1. L. spixosa. 



1. Branches not spinescent; stem without tufts of wool at base; leaves other- 

 wise (2). 

 2. Leaves grasslike, linear, entire, conspicuous, up to 10 cm. long; involucre 

 18 to 20 mm. high; achenes at least 10 mm. long; plant perennial. 



2. L. GRAXDIFLORA. 



2. Basal leaves obovate or oblanceolate, repand-toothed or lobed, those of the 

 stem reduced and inconspicuous; involucre about 5 mm. high; achenes 

 about 3 mm. long; plant annual 3. L. exigua. 



1. Lygodesmia spinosa Nutt., Amer. Phil. Soc. Trans, ser. 2, 7: 444. 



1841. 



Flagstaff to the Little Colorado River (Coconino County), 6,500 

 to 7,500 feet, August and September. Montana to British Columbia, 

 northern Arizona, and California. 



2. Lygodesmia grandiflora (Nutt.) Ton*, and Gray, Fl. North Amer. 2: 



485. 1843. 



Erythremia grand iflora Nutt., Amer. Phil. Soc. Trans, ser. 

 2,7:445. 1841. 



Navajo and Coconino Counties, about 5,000 feet, common on sandy 

 plains, often with grasses, May and Juno. Wyoming to Idaho, south 

 to New Mexico and central Arizona. 



