Rydrerg : Studies on the Rockv Mountain Im.ora 682 



his Exotic Mora, />/. igj; & /^y, identifies Colignon's plant as 

 Abronia uuibcllata. The type of Iricratus is the same, and that of 

 Cycloptera is A. cycloptcra. 



Fruit narrowly winged or crested ; wings or crests not completely encircling the fruit. 

 Fruit biturbinate, /. e., tapering at both ends, irregularly ridged or crested. 

 Flowers about 2 cm. long ; limb 5-10 mm. wide. 



Hracts broadly obovate, over l cm. long. I. A. /radians. 



Hracts ovate-lanceolate, less than i cm. long. 2. A. nui/al.i. 



Flowers about I cm. long ; limb 3-5 mm. wide ; bracts ovate to lanceolate- 

 ovate, about 5 mm. long. 

 Petioles of the stem-leaves shorter than the very thick blades ; plant low, 



about I dm. high. 3. A. ptnnila. 



Petioles of the stem-leaves much longer than the moderately thick blades ; 

 plant slender, 2-4 dm. high. 4. A. ammophtla. 



Fruit turbinate or obpyramidal, /. <•., almost truncate above, distinctly winged ; the 

 wings very broad above. 

 Plant almost acaulescent ; stem and leaves greatly surpassed by the long 



peduncles. 5. A. nana. 



Plant with an elongated stem. 



Bracts broadly ovate or obovate, acute or obtusish. 



Stem distinctly viscid-pubescent ; leaves scabrous-puberulent ; bracts 

 I-1.5 cm. long. 

 Blades of the stem-leaves elliptic ; bracts broadly obovate, 12- 



15 mm. wide, obtusish. 6. A. salsa. 



Blades of the stem-leaves lanceolate; bracts oval, acute, about 

 6-7 mm. wide. 7. A.fallax. 



Stem finely puberulent or glabrous ; leaves glabrous ; bracts 5-8 mm. 

 long. 

 Stem puberulent. 8. A. elliptica. 



Stem glabrous. 9. A. glabra. 



Bracts oblong-lanceolate or lanceolate, attenuate or cuspidate. 



Stem glabrous. 10. A. lanceolata. 



Stem more or less pubescent. 



Stem puberulent ; wings with double lamina, coriaceous. 



11. A. Carlefoni. 

 Stem villous ; wings with single lamina, membranous. 



12. A. villosa. 

 Fruit completely surrounded by the broad netted-veined membranous wings. 



Flowers 3 cm. or more long ; limb about I cm. wide ; peduncles longer than the 



•eaves. 13. A. cydoptera. 



Flowers 1.5-2 cm. long; limb about 5 mm. wide. 



Stem glabrous or nearly so ; peduncles often nearly equalling the leaves. 



14. A. pedunculata. 

 Stem densely pubescent ; peduncles at least in flower much shorter than the 

 leaves. 15. A. viicrantha. 



I. Abronia fragrans Nutt.; Hook. Kew Journ. 5: 261, 1853 

 On the plains from South Dakota to Montana, Idaho, New 

 Mexico and Kansas. 



