FLOWERING PLANTS AND FERNS OF ARIZONA 593 



8. Mentzelia rusbyi Woot., Torrey Bob. Club Bui. 25: 261. 1898. 



Xuttallia rusbyi Cockerell, Amer. Ent. Soc. Trans. 32: 300. 

 1906. 



Coconino County, 6,000 to 8,500 feet, mostly in yellow pine forests, 

 July to September. Wyoming to New Mexico and northern Arizona. 



Plant coarser, more robust, and larger leaved than in any other of 

 the Arizona species. 



9. Mentzelia pumila (Nutt.) Torr. and Grav, Fl. North Amer. 1: 535. 



1840. 



Bartonia pumila Nutt., Gen. PL 1: 299. 1818. 



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

 Yuma Counties, 3,600 to 8,000 feet, Slay to August. Wyoming and 

 Utah to western Texas, Arizona, California, and northern Mexico. 



Blazing-star. The distribution in Arizona given in the preceding 

 paragraph is that of the typical form, and of the scarcely distinguish- 

 able var. proeera (Woot. and Standi.) J. Darlington, characterized 

 by acute or acuminate petals, and broad outer filaments. Much more 

 common and abundant in Arizona is var. mult i flora (Nutt.) Urban 

 and Gilg (M. ?nulti flora Gray), with more obtuse petals (these often 

 appearing acute in dried specimens) and narrower outer filaments. 

 This variety occurs throughout the State at altitudes of 100 to 7,000 

 feet, preferring sandy soil, especially abundant in dry stream beds 

 and along roads. All forms of M. pumila have freely branched stems 

 and rather large flowers with petals bright yellow when fresh and 1 

 to 2 cm. long. 



10. Mentzelia integra (M. E. Jones) Tidestrom, Contrib. U. S. Natl. 



Herbarium 25: 362. 1925. 



Mentzelia multi-flora var. integra M. E. Jones, Calif. Acad. Sci. 



Proc. ser. 2, 5: 689. 1895. 

 Nuttallia integra Rydb., Torrey Bot, Club Bui. 40: 61. 1913. 



Kaibab Trail, Grand Canyon, Coconino County (Clover 4151), 

 Virgin River, Mohave County (Purpus 6192). Southern Utah and 

 northern Arizona. 



It is doubtful that this form is more than a variety of M. pumila. 



11. Mentzelia puberula J. Darlington, Mo. Bot. Gard. Ann. 21: 177. 



1934. 



Gila Mountains (Yuma County), 500 to 1,000 feet, dry rocky slopes, 

 March, and flowering occasionally after summer rains. Southwestern 

 Arizona and southeastern California. 



An undershrub, not more than 0.5 m. high. 



4. EUCNIDE. Rockxettle 



Plant herbaceous, hispid with stinging hairs; leaf blades broadly 

 ovate, subcordate, few-toothed; flowers few in terminal cymes, the 

 petals pale yellow or cream-colored, about 5 cm. long; filaments of 

 the stamens all alike, none of them petaloid. 



