FLOWERING PLANTS AND FERNS OF ARIZONA 991 



2. Plummera ambigens Blake, Wash. Acad. Sci. Jour. 19: 276. 1929. 



Known only from the lower slopes of the Pinaleno Mountains 



Graham County), where it is abundant at about 5.000 feet, in 



stony sterile soil, July to October, type from this locality [Peebles 



etaf. 4395). 



102. TAGETES. Marigold 



Herbaceous or suffrutescent ; leaves mostly opposite, entire or 

 pinnately divided, dotted with translucent oil glands; heads small or 

 large, radiate or discoid, yellow; phyllaries 1 -seriate, united into a 

 toothed cup or tube, dotted with oil glands; achenes slender; pappus 

 of 3 to 6 paleae. 



Several species, particularly Tagetes erecta and T. pofvla. are com- 

 monly cultivated as ornamentals under the names African marigold 

 and French marigold. 



K(y to the species 



1. Tall suffrutescent perennial: rays large, about 10 mm. long, bright yellow; 

 leaves with 3 to 7 mostly lanceolate divisions, these 4 To 12 mm. wide. 



1. T. LEMMONI. 



1. Dwarf annual: rays tiny (or wanting'. 2 mm. long or less, pale yellow; leaves 

 filiform and entire, or of 3 or 5 filiform divisions 2. T. micraxtha, 



1. Tagetes lemmoni A. Gray, Amer. Acad. Arts and Sci. Proc. 19: 



40. 1883. 



Mountains of Cochise and Pima Counties, 6,000 to 7.500 feet, 

 rich moist soil in canyons, August to October, type from the Huachuca 

 Mountains (Lemmon in 1882). Known only from southeastern 

 Arizona. 



A handsome but very ill-scented plant. 



2. Tagetes micrantha Cav., Icon. PL 4: 31. 1797. 



Pinetop, southern Xavajo County, and mountains of Cochise and 

 Santa Cruz Counties, about 6,000 feet, August and September. 

 Western Texas to southeastern Arizona and central Mexico. 



103. DYSSODIA 



Annual or perennial herbs, or suffruticose; leaves opposite or alter- 

 nate, entire to pinnatisect, marked with translucent glands; heads 

 small to rather large, radiate, yellow or orange, or the rays rarely 

 white; involucre usually calyculate (subtended by bractlets), the 

 principal phyllaries equal, usually 2-seriate and united at base, or 

 almost to the apex; pappus of 10 to 15 squamellae or paleae. often 

 tipped with 1 or 3 bristles or dissected into numerous bristles. 



Dyssodia papposa and D. acerosa are sometimes abundant on over- 

 grazed land and are regarded as range pests. The former is suspected 

 of being poisonous to livestock, but definite information is lacking. 



Kt y to the species 



1. Heads large, the disk 1.5 to 2 cm. high or more: pappus of 10 to 15 paleae, 

 each dissected into numerous bristles (2). 

 2. Stem glabrous: leaves pinnately 3- or 5-parted into narrow lobes. 



1. D. POROPHYKLOIDES. 



2. Stem densely puberulous or hispidulous: larger leaves oval or ovate, merely 

 spinulose-toothed or with small basal lobes 2. D. cooperi. 



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