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



2. Abronia angustifolia Greene, Pittonia 3: 344. 1898. 



Graham, Maricopa, Pinal, and Cochise Counties, 1,000 to 4,000 

 feet, March to July (occasionally September). Western Texas and 

 Chihuahua to Arizona. 



The form occurring in this State is var. arizonica (Standi.) Kearney 

 and Peebles (A. arizonica Standi.), which is usually more pubescent 

 and broader leaved than typical A. angustifolia. Specimens without 

 fruit are difficult to distinguish from A. villosa. The type of A. 

 arizonica was obtained in Arizona (Vasey in 1882, without definite 

 locality) . 



3. Abronia nana S. Wats., Amer. Acad. Arts and Sci. Proc. 14: 294. 



1870. 



Coconino and Mohave Counties, especially in the Grand Canyon 

 region, 3,000 to 5,000 feet, April to May. Southern Utah and Nevada 

 and northern Arizona. 



Specimens having a bright pink perianth limb have been collected 

 at the Grand Canyon (Collom in 1940). 



4. Abronia fragrans Nutt. ex Hook., Jour. Bot. and Kew Gard. Misc. 



5: 261. 1853. 

 North of Ganado, Apache County (Peebles 13497), east of Tuba, 

 Coconino County (Harrison and King 8715), 5,000 to 6,000 feet. 

 South Dakota to Idaho, south to Chihuahua and northern Arizona. 



5. Abronia elliptica A. Nels., Torrey Bot. Club. Bui. 26: 7. 1899. 

 Apache County to Mohave County, 1,800 to 7,000 feet, common in 



northeastern Arizona, April to June. Wyoming to northern New 

 Mexico and Arizona. 



Perhaps only varietally distinct from A. fragrans Nutt., with which 

 it seems to intergrade in Arizona. 



11. TRIPTEROCALYX 



Plants similar to Abronia but often with a 4-lobed perianth limb and 

 with the body of the fruit harder, spindle-shaped, completely sur- 

 rounded by the 2 to 4 broad, thin, nearly transparent, conspicuously 

 reticulate-veined wings. 



The fruits with their large fish-scalelike wings are conspicuous. 



Key to the species 



1. Perianth less than 2 cm. long, sparsely pubescent or glabrate, the limb greenish 

 or pink 1. T. micranthus. 



1. Perianth more than 2 cm. long, copiously pubescent, the limb pink outside, 

 white within 2. T. wootonii. 



1. Tripterocalyx micranthus (Torr.) Hook., Jour. Bot. and Kew 

 Gard. Misc. 5: 261. 1853. 



Abronia micrantha Torr. and Frem. in Frem., Exped. Rocky 

 Mount. Rpt. 92. 1843. 



Mohave County, at Pierce Ferry, 1,700 feet (Jones 5077av), and 

 Pipe Springs, 4,700 feet (Peebles 13068), April to June. North Dakota 

 and Montana to Kansas, Nevada, and Arizona. 



The Arizona form is T. pedunculatus (M. E. Jones) Standi. (Abronia 

 micrantha var. pedunculata M. E. Jones), which seems, at most, to be 

 only varietally distinct from T. micranthus. 



