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



Lukachukai Mountains, Apache County {Goodman and Payson 2848), 

 but is much more abundant in adjacent New Mexico and Colorado. 

 Subsp. sileri (A. Gray) Keck is common from the Kaibab Plateau 

 region (Coconino and Mohave Counties) to Yavapai County, and is 

 occasional southeastward to Cochise County, also common in southern 

 Utah. The var. viridis Keck is less frequent than subsp. sileri, but 

 occupies the same range as far south as Gila County. 



30. Penstemon discolor Keck, Torrey Bot. Club Bui. 64: 379. 1937. 

 Known only from the type locality, Bear Canyon, Santa Catalina 



Mountains (Pima County), 6,100 to 7,000 feet, June and July, the 

 type collected by Forrest Shreve (No. 5319). 



31. Penstemon thurberi Torr., U. S. Rpt. Expl. Miss. Pacif. 7 3 : 



15. 1856. 



Leiostemon thurberi Greene, Leaflets 1: 223. 1906. 

 Penstemon scoparius A. Nels., Wyo. Univ. Pubs. Bot. 1: 132. 

 1926. 



Mohave and Yavapai Counties, southeastward to Pima and Cochise 

 Counties, 2,000 to 4,000 feet, open sandy or stony slopes, March to 

 June, type of P. scoparius from West Wells (Goodding 1037). New 

 Mexico, Arizona, California, and Baja California. 



This species is ordinarily distinctly set off from the next, but there 

 is some evidence of their mixing in west-central New Mexico. 



32. Penstemon ambiguus Torr., Ann. Lye. N. Y. 2: 228. 1828. 

 Navajo and Coconino Counties, 4,500 to 6,500 feet, open sandy 



mesas and grassland, rather common in the Painted Desert, summer. 

 Kansas and Texas to Nevada and northern Arizona. 



The typical form of the species, with puberulent herbage, occurs 

 farther east. The glabrous Arizona form, subsp. laevissimus Keck, 

 ranges from southwestern Texas to Utah and Nevada. In the Hopi 

 country it has been called " cow-tobacco." 



33. Penstemon dasyphyllus A. Gray in Torr., U. S. and Mex. Bound. 



Bot. 112. 1859. 

 Cochise, Santa Cruz, and Pima Counties, 3,600 to 5,000 feet, 

 open gravelly slopes, April and May and again in late summer. 

 Western Texas to southeastern Arizona and Chihuahua. 



34. Penstemon stenophyllus A. Gray in Torr., U. S. and Mex. 



Bound. Bot. 112. 1859. 



Penstemon rubescens A. Gray, Amer. Acad. Arts and Sci. 

 Proc. 19: 92. 1883. 



Huachuca and Patagonia Mountains (C@chise and Santa Cruz 

 Counties), 4,000 to 5,500 feet, open canyons and slopes, August and 

 September. Southeastern Arizona, Sonora, and Chihuahua. 



The type of the species came from Sonora. The type of P. rubescens 

 came from near Fort Huachuca, Cochise County (Lemmon) and was 

 blue-flowered, although Gray mistook the color for red. The flowers 

 of this and the preceding species are a rich violet blue when fresh. 



