Heller: Plants from Western North America 313 



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Our no. 3044a, collected on the right bank of the Snake 

 River, near Lewiston, Nez Pcrces county, Idaho, May 11, 1896, 



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altitude about 800 feet. This species was associated with Lcpidiunt 

 Idahocnse^whxch it resembles in manner of growth and appearance 

 of herbage. The principal differences are found in the inflores- 

 cence, as will be seen by comparing the two descriptions. L, siniile 



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is also less inclined to branch, and the branches ascending at an 

 ■acuter angle. The type is in my private herbarium. 



Ptelea rhombifolia sp. nov. 



A shrub, about 2.5 meters high, branching above, the branches 

 spreading, light brown, or grayish, the older ones usually smooth, 

 those of the season^s growth pubescent with short curved hairs ; 

 leaves trifoliolate, the petioles and lower surfaces covered with 

 "tomentose hairs, the upper surfaces also pubescent, but less so, 

 ■and greener ; petioles about 5 cm. long ; leaflets somewhat rhom- 

 bic ovate, or rhombic orbicular, the largest about 5 cm. long, and 

 4 cm. wide, their apices either rounded or slightly pointed, midrib 

 yellowish, prominent, as are also the pinnate veins : inflorescence 

 .strongly pubescent, including the petals and the bases of the sta- 

 mens ; petals creamy white, obovate-oblong, about 4 mm. long ; 

 rsamara almost orbicular, about 1.4 cm. in diameter, reticulate. 



My no. 1582, collected at San Antonio, Bexar county, Texas, 

 April 27, 1894, altitude 600 feet. The specimens were collected 

 in a wooded tract lying between the right bank of the river and 

 'the Southern Pacific railroad track. Specimens were distributed 

 under the name ^^ Ptelea trifoliata )nollis^' but can hardly be referred 

 to that species, which has a more eastern distribution. The type 

 is in my private herbarium. 



To Ptelea rhombifolia I would also refer Dr. D. T. Mac- 



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Dougal's no. 139, collected in Walnut Cafion, near Flagstaff, 



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Arizona, June 18, 1898. 



Microsteris diffusa sp. nov. 



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Diffusely branched from the base, 15-25 cm. high, often 30 

 cm. broad, pubescent throughout with chaffy, spreading or twisted 

 h^irs, those on the upper portion of the plant glandular : leav^es all 

 sessile, the lowest ones oblong-oval, nearly glabrous, the others 

 lanceolate, acute, usually about 4 cm. long, and from 5 mm. to i 

 ^cm. wide ; flowers rather numerous ; calyx i cm. long, the tubular 



