WOOTON AND STANDLEY FLORA OF NEW MEXICO. 325 



KEY TO THE GENERA. 



Flowers in long racemes, on short leafy branches of the year. . 1. Padus (p. 325). 

 Flowers in corymbs or umbels, on short stems of the previous 

 year, preceding the leaves. 



Stone of the fruit flattened, with more or less acute edges. . 2. Prunus (p. 327). 



Stone of the fruit spheroidal, little or not at all flattened.. 3. Cerasus (p. 327). 



1. PADUS Borckh. Chokecherry. 



Large shri^bs or small trees with smooth dark-colored bark; flowers numerous, in 

 elongated racemes terminating short leafy branches of the year; hypanthium sphe- 

 roidal, sometimes campanula te; sepals 5, short, persistent or deciduous with a part 

 of the hypanthivmi; petals white, with the numerous stamens on the throat of the 

 hypanthium; carpels solitary; ovary 1-celled, 2-ovuled; drupe small, usually 1 cm. 

 in diameter or less, astringent, not glaucous. 



The fruits of these trees and shrubs were eaten by the Indians. They lack the 

 astringent flavor of the eastern chokecherries. 



key to the species. 

 C'alyx persistent in fruit. 



Young branches densely tawny-pubescent; young fruit pu- 

 bescent 1 . P. rufula. 



Young branches and fruit glabrous 2. P. virens. 



Calyx deciduous soon after anthesis. 



Plants glabrous throughout 3. P. melanocarpa. 



Plants pubescent on the peduncles, petioles, and lower surface 

 of the leaves. 

 Leaves not glaucous beneath at maturity, of about the 



same color on both surfaces 4. P. pumicea. 



Leaves pale beneath at maturity. 



Pedicels longer than the fruit, slender; seeds 8 to 10 



mm. in diameter 5. P. mescaleria. 



Pedicels shorter than the fruit, stout; seeds 7 mm. in 

 diameter or less. 

 Pedicels glabrous; racemes slender; leaves ellip- 

 tic, narrowed at the base; buds narrowly 



lanceolate in outline 6. P. calophylla. 



Pedicels pubescent; racemes stout; leaves ob- 

 long to ovate or obovate, rounded to sub- 

 cordate at the base; buds ovoid 7. P. valida. 



1. Padus rufula Woot. & Standi. Contr. U. S. Nat. Herb. 16: 132. 1913. 



Type locality: On the West Fork of the Rio Gila, New Mexico. Type collected 

 by Wooton, August 6, 1900. 



Range: Mountains of southwestern New Mexico, southeastern Arizona, and adja- 

 cent Mexico. 



New Mexico: Mogollon Moim tains; Black Range. 



2. Padus virens Woot. & Standi. Contr. U. S. Nat. Herb. 16: 132. 1913. 



Type locality: Van Pattens Camp in the Organ Mountains, New Mexico. Type 

 collected by Standley, June 6, 1906. 



Range: Southern New Mexico and Arizona. 



New Mexico: Organ Mountains; Bear Mountains; San Francisco Mountains; 

 Mogollon Mountains; Burro Mountains; Kingston; White and Sacramento mountains. 

 Canyons and hills, in the Upper Sonoran Zone. 



