FLOWERING PLANTS AND FERNS OF ARIZONA 969 



1. Layia glandulosa (Hook.) Hook, and Am., Bot. Beechey Voy. 358. 

 1840. 



Blepharipappus glandulosus Hook., Fl. Bor. Amer. 1: 316. 

 1834. 



Navajo County to Mohave County, south to Santa Cruz and Pima 

 Counties, up to 5,000 feet, dry slopes and mesas, not abundant, 

 March to June. Idaho and British Columbia to southwestern New 

 Mexico and Baja California. 



Plant handsome in flower, with pure white rays. 



81. PSILOSTROPHE 



Herbs or shrubs, more or less woolly ; leaves alternate, entire or the 

 lower ones pinnatifid; heads small, radiate, yellow; receptacle naked; 

 rays persistent, becoming papery; achenes slender; pappus of 4 to 6 

 hyaline paleae. 



Key to the species 



1. Stem and branches densely pannose-tomentose with white wool; leaves linear 

 or narrowly linear-lanceolate, entire; plant definitely shrubby; heads 

 mostly solitary at the tips of the branches, slender-peduncled. 



1. P. COOPERI. 



1. Stems and branches not pannose-tomentose; leaves (at least the basal ones) 

 usually spatulate to obovate; plants herbaceous (2). 

 2. Stem and leaves rather densely lanate or tomentose; heads in close cymose 



clusters at the tips of the stem and branches 2. P. tagetinae. 



2. Stem and leaves green, thinly pilose or pilosulous; heads usually scattered 

 or in loose cymes 3. P. sparsiflora. 



1. Psilostrophe cooperi (A. Gray) Greene, Pittonia 2: 176. 1891. 



Biddellia cooperi A. Gray, Amer. Acad. Arts and Sci. Proc. 7: 

 358. 1868. 



Mohave and Yavapai Counties to Graham, Pima, and Yuma Coun- 

 ties, 2,000 to 5,000 feet, mesas and plains, common, flowering through- 

 out the year, type from Fort Mohave (Cooper in 1861). Southern 

 Utah (and southwestern New Mexico?) to southern California and 

 northern Baja California. 



Plant showy and handsome in flower. 



2. Psilostrophe tagetinae (Nutt.) Greene, Pittonia 2: 176. 1891, 



as P. tagetina. 



Riddellia tagetinae Nutt., Amer. Phil. Soc. Trans, ser. 2, 7: 



371. 1841. 

 Psilostrophe tagetina var. Janata A. Nels., Biol. Soc. Wash. 



Proc. 16: 22. 1903. 

 Psilostrophe lanata Prain, Index Kew. Suppl. 3: 145. 1908. 



Apache, Navajo, Coconino, Greenlee, and Cochise Counties, 4,000 

 to 7,000 feet, open plains and mesas, and yellow pine forests, April 

 to October. Western Texas (and southern Colorado?) to Arizona 

 and Chihuahua. 



It is reported that sheep are sometimes fatally poisoned by this plant. 



