WOOTON AND STANDLEY FLOEA OF NEW MEXICO. 699 



1, Melampodium leucanthum Torr. & Gray, Fl. N. Amer. 2: 271. 1842. 



Type locality: Texas. 



Range: Colorado and Kansas to Arizona and Texas and southward. 



New Mexico: Bernal; Pecos; Nara Visa; Clayton ; Socorro Mountain; Albuquerque ; 

 Knowles; Melrose; Fort Bayard; Mangas Springs; Middle Fork of the Gila; Organ 

 Mountains; Roswell; south of Stanley. Dry plains and hills, in the Lower and Upper 

 Sonoran zones. 



The ray flowers of this species are normally a clear, bright white, but not infre- 

 quently turn pink with age, especially late in the season, and plants with pinkish 

 rays are occasional. 



56. PARTHENITTM L. 



Herbaceous or woody biennials or perennials with alternate, pubescent, variously 

 lobed or pinnatifid leaves, and numerous corymbs of small heads of white flowers; 

 involucre of few broad appressed bracts in about two series; achenes oval or obovate, 

 usually pubescent, with a narrow callous margin; pappus of 2 chaffy awns or scales. 



KEY TO THE SPECIES. 



Herb ; leaves twice pinnatifid 1. P. lyratum. 



Low shrub ; leaves few-lobed 2. P. incanum. 



Statements have been made that P. argentatum, the Mexican rubber plant or 

 "guayule," occurs in New Mexico, but so far as we know there is no foundation for 

 these reports, that species ranging much farther south . 



1. Parthenium lyratum A. Gray, Syn. Fl. 1^: 244. 1884. 

 Partheniumhysterophorus lyratum A. Gray, Proc. Amer. Acad. 17: 216. 1882. 

 Type locality: Western Texas. 



Range: Western Texas and southern New Mexico; also in Mexico. 

 New Mexico: Soledad Canyon; Hondo Hill; Guadalupe Mountains; Carlsbad; 

 Lake Valley. Dry hills, in the Upper Sonoran Zone. 



2. Parthenium incanum H. B. K. Nov. Gen. & Sp.-4: 260. pi. 391. 1820. Mariola. 

 Type locality: "Colitur in horto botanico Mexicano." 



Range: Western Texas to southern Arizona and southward. 



New Mexico: Socorro; Mangas Springs; Rincon; Tucumcari; Cuehillo; Florida 

 Mountains; Tortugas Mountain; Organ Mountains; WTiite Mountains. Dry hills and 

 along arroyos, in the Lower Sonoran Zone. 



This plant has been used for the production of rubber. For this purpose, however, 

 it is far less valuable than the Mexican rubber plant, or "guayule," mentioned above. 



57. BERLANDrERA DC. 



Coarse canescent perennial herbs with alternate, simple or lyrate-pinnatifid leaves 

 and large pedunculate heads with showy yellow rays; bracts in about 3 series, the 

 outermost small and foliaceous, the inner thin, membranaceous in age; achenes flat, 

 obovate, wingless, unicostate on the inner surface; pappus mostly obsolete. 



KEY TO the species. 



Leaves all pinnatifid; heads numerous 1. B. lyrata. 



Leaves merely crenate; heads few 2. B. macrophylla. 



1. Berlandiera lyrata Benth. PI. Hartw. 17. 1839. 

 Berlandkra incisa Torr. & Gray, Fl. N. Amer. 2: 282. 1842. 

 Type locality: Mexico. 

 Range : Arkansas and Texas to Arizona and Mexico. 



