942 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



laries broad; rays fertile; disk flowers sterile; receptacle paleaceous; 

 ray achenes strongly flattened, epappose, adnate at base to the sub- 

 tending phyllary and the spatulate pales of the 2 opposed sterile 

 flowers, the whole falling together. 



1. Berlandiera lyrata Benth., PL Hartw. 17. 1839. 



Cochise, Santa Cruz, and eastern Pima Counties, 4,000 to 5,000 

 feet, plains and mesas, May to September. Kansas and Arkansas 

 to Texas, southeastern Arizona, and northern Mexico. 



The var. macrophylla A. Gray (B. macrophylla M. E. Jones), of 

 which the type was collected in southern Arizona by Lemmon, is 

 occasional in Cochise County. It differs from typical B. lyrata in 

 having merely crenate, instead of lyrate-pinnatifid leaves. The 

 flower heads of B. lyrata are reported to have been used by the Indians 

 as seasoning in foods. 



42. ENGELMANNIA 



Perennial herb, rough-pubescent; leaves alternate, deeply pinnatifid; 

 heads medium -sized, yellow, radiate, slender-peduncled ; involucre 

 graduated; rays fertile; disk flowers hermaphrodite but sterile; 

 receptacle paleaceous; ray achenes strongly flattened, each adnate at 

 base to the subtending phyllary and the pales of the opposed outer 

 disk flowers, the whole falling away together; pappus in the ray flowers 

 of an unequally lobed or toothed crown, in the disk flowers reduced. 



*1. Engelmannia pinnatifida Nutt., Amer. Phil. Soc. Trans, ser. 2, 7: 

 343. 1840. 

 Kansas to Louisiana, west to Colorado and New Mexico, south to 

 northern Mexico (reported from Arizona), dry hills and prairies, May 

 to September. 



43. PARTHENIUM 



Low, branching, gray-tomentulose shrub ; leaves alternate, pinnati- 

 fid, with blunt roundish lobes; heads small, white, cymose-panicled ; 

 rays fertile, very small; disk flowers sterile; achenes small, flattened, 

 surrounded by a narrow callous margin, this adnate at base to the 

 pales of the 2 opposed disk flowers and the subtending phyllary, at 

 length tearing away from the achene below but remaining attached at 

 apex. 



1. Parthenium incanum H. B. K., Nov. Gen. et Sp. 4: 260. 1820. 



Grand Canyon (Coconino County), Montezuma Well (Yavapai 

 County), and Cochise and Pima Counties, 3,000 to 6,000 feet, dry 

 plains and mesas, usually in ' 'caliche" soil, June to October. Western 

 Texas to Arizona and Mexico. 



Mariola. A small shrub, common in the Lower Sonoran zone in 

 the Grand Canyon (V. Bailey), and in southeastern Arizona. The 

 plant is rarely browsed. It contains rubber like that of guayule 

 (Parthenium argentatum A. Gray), but in smaller amount. Guayule, 

 which may be distinguished by its narrowly lanceolate leaves, these 

 entire or laciniate-toothed or lobed with acuminate lobes, and finely 

 silvery-pubescent on both sides, has been cultivated in Arizona as a 

 source of rubber. 



44. PARTHENICE 



Branching, cinereous-puberulent annual; leaves alternate, ovate, 

 long-petioled, toothed; heads disciform, numerous, panicled, greenish 



