280 MISC. PUBLICATION 42 3, IT. S. DEPT. OF AGRICULTURE 



10. Seeds black or very dark brown, shining; terminal spike erect or 

 nearly so (11). 

 11. Spikes usually slender; bracts commonly less than 5 mm. long; 

 seeds orbicular; sepals equaling or shorter than the fruit. 



10. A. HYBRIDUS. 



11. Spikes usually stout; bracts commonly more than 5 mm. long; 

 seeds obovoid or broadly oval; sepals usually longer than the 



fruit 11. A. powellii. 



9. Sepals of the pistillate flowers mostly obtuse or truncate at apex (12). 



12. Plant glabrous or very nearly so; stems slender, usually less than 50 



cm. long; flowers in slender, more or less interrupted, leafy spikes. 



12. A. WRIGHTII. 

 12. Plant villous, at least in the inflorescence; stems stout, usually more 

 than 50 cm. long; flowers in ample, usually dense, panicles of 

 spikes (13). 

 13. Capsule ovoid, considerably surpassing the calyx. 



13. A. CRUENTUS. 



13. Capsule subglobose, not surpassing and usually considerably 



shorter than the calyx 14. A. retroflexus. 



1. Amaranthus obcordatus (A. Gray) Standi., North Amer. Fl. 21: 



107. 1917. 



Amblogyne urceolata var. obcordata A. Gray, Amer. Acad. Arts 

 and Sci. Proc. 5: 168. 1861. 



Cochise and Pima Counties, 2,200 to 3,700 feet, apparently not 

 common. Western Texas to Arizona and northern Mexico. 



2. Amaranthus palmeri S. Wats., Amer. Acad. Arts and Sci. Proc. 12: 



274. 1877. 



Graham County to Yavapai County, south to Cochise, Santa Cruz, 

 and Pima Counties, 5,000 feet or lower. Kansas to Texas, Arizona, 

 California, and central Mexico. 



Carelessweed, redroot, quelite, bledo. A tall, coarse, weedy plant, 

 abundant in river bottoms and irrigated land. 



3. Amaranthus fimbriatus (Torr.) Benth. in S. Wats., Bot. Calif. 2: 



42. 1880. 



Sarratia berlandieri var. fimbriata Torr., U. S. and Mex. Bound. 

 Bot. 179. 1859. 



Gila County to Mohave County, south to Cochise, Pima, and 

 (probably) Yuma Counties, below 4,000 feet, commonly in sandy 

 washes. Southern Utah and Nevada to Arizona and northwestern 

 Mexico. 



The typical form with fimbriate margins of the sepals, is much the 

 more common in Arizona, but var. denticulatus Uline and Bray (A. 

 venulosus S. Wats.), with sepals entire or denticulate, has been 

 collected at Tucson, Pima County (Tourney, Thornber), and at Casa 

 Grande, Pinal County (Jones). 



4. Amaranthus pringlei S. Wats., Amer. Acad. Arts and Sci. Proc. 22: 



476. 1887. 

 Cochise, Santa Cruz, and Pima Counties, 3,500 to 5,500 feet. 

 Western Texas to Nevada, Arizona, and northern Mexico. 



5. Amaranthus gracilis Desf., Tabl. Bot. 43. 1804. 



Sacaton (Pinal County), a casual introduction from the Tropics, 

 probably not established in Arizona. 



