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GREENE PTKLEA IIS" THE WEST AJN'D SOUTHWEST. 



53 



SYNOPSIS OF THE SPECIES, 



TWIGS Avhen not velvety-hoary either chestnut -colored or 

 <hirker, never Avhitiwh or straw-colored. 

 Upper face of foliage more or less definitely bluish-green 

 or glaucescent, never clear bright green. 



Leaves in maturity thin^ or tliinnish, never hard and 

 subcoriaceous; samaras in all these very large, thin 

 and plane, the whig ample, the bo<ly pinall in pro- 

 portion. 



Leaflets <lark, scarcely bluish-green, not glaucous, 

 only lighter beneath, glabrous, odd one obovate 

 to long-ovate, 9 cm. long; samaras suborbicular, 

 2 cm. long, nearly as wide. 



Leaflets definitely blue-green on both faces, nearly 

 glabrous, odd one ovate, 5 cm. long; samaras 

 suborbicularj retuse at base, obcordate at sujn- 

 mit. 



Leaflets dull with pubescence above, even more so 

 beneath; odd one broadly obovate, 4 cm. long; 

 samaras suborl)icular, L5 cni, loi^g, sharply 

 Mrinkledand with lunjj^itudinal tsharp ridge. 



Leaflets dull and pul>escent, odd one elliptic- 

 obovate, 6.5 cm. long; samaras round-oval, 2.5 

 cm. long, sharjtly Avrinkled, but with no median 

 ridge. 



Leaflets i^ale, gray-green Mitli pubescence, odd one 

 obovate-elliptic, 5 cm. long, of firmer texture; 

 largo samaras broadly somewhat obovate, ob- 

 tuse, 3 cm. long, obtusely wrinkled and much 

 dotted. 



Leaflets less pubesceid, bluisli-green only when 

 young, very firm wlien mature, odd one broadly 

 obovate, 7 cm. long, cuspidate-pointed; samaras 

 suborbicular, 3 cm. long, subcordate. 



Leaflets very pale, beneath whitish Avith bloom, 

 hirge, odd one oval to obovate, 7 cm. long, acut- 

 ish; samaras small for the foliage, 2 cm. long, 

 obtuse at base, at apex emarginate. 



Leaflets very pale, whitish beneath with bloom, 

 almost so above, small, firm, odd one broadly 

 rhombic-lanceolate, 4.5 cm. long; samaras large 

 for the foliage, rounded, but truncate at both 

 ends. 



Leaflets pale, whitish beneath with bloom and 

 while down, odd one ovute, 5 cm. long, obtuse, 

 crenate; samaras orbicular, 1.5 cm. long and 

 wide. 



Leaflets glaucous on both faces, tomentulose be- 

 neath, odd one ovate-elliptic, 5 cm. long, suljen- 

 tire; samaras broader than long, with cordate 

 lobes at each end, the breadth 2 cm. 



L P. aquiUna, 



2. P. isophjUa 



3. P. prominula 



4. P. wrightiana 



5. P antonina. 



6. 1\ rhomhifoHa 



7. P. formosa. 



8, P. tillosida. 



9. P tortKom. 



10. P suhirdegnu 



