128 MALACEAE 



Leaf-blades thin, usually oval. 7. A. florida. 



Leaf-blades firm, usually suborbicular. 8. A. alnifnlia. 

 Leaves more or less permanently pubescent on both sides, more or less pale. 



Leaves neither coarsely toothed nor strongly veined. 9. A. orcophila. 



Leaves coarsely toothed and strongly veined. 10. A. mormonica. 

 Fruit even in age more or less pubescent, orange or yellow, not juicy; styles mostly 

 3 or 2. 

 Leaves coarsely toothed; branches gray. 



Leaf-blades suborbicular, tnmcate at the apex. 



Leaves dentate; teeth acute. 12. A. Bakeri. 



Leaves crenate, teeth broad, rounder. 13. A. crenata. 



Leaf-blades oval, acute to rounded at the apex. 14. A. utahensis. 



Leaves finely toothed; breuiches brown or cherry-red. 15. A. prunifolia. 



2. PERAPHYLLUM Nutt. Squaw Apple, Wild Crab. 



1. P. ramosissimum. 



3. SORBUS L. Mountain Ash. 



Leaflets acute or acuminate at the apex, serrate to near the base; inflorescence broad 

 and flat-topped. 

 Leaflets linear-lanceolate, gradually acuminate, at least flve times as long as broad. 



1. S. angustifolja. 

 Leaflets elliptic or oblong, abruptly acuminate or acute, 2-3 times as long as broad. 



2. S. scopulina. 

 Leaflets mostly roimded at the apex, entire towards the base; inflorescence small, usually 



roimd-topped. 3. S. occidentalis. 



4. CRATAEGUS L. Haw or Hawthorn. 



Fruit black or nearly so when ripe; nutlets irregularly pitted on the faces; leaves glabrate 

 beneatli, more or less pubescent above. 

 Inflorescence glabroiLs; spines mostly slender. 



Leaf-blades narrow, rhombic-oblanceolate or eUiptic, scarcely lobed. 



Leaf-blades crenate; fruit 7-S mm. in diameter; nutlets 5. 1. C. saligna. 

 Leaf-blades irregularly serrate; fruit 8-10 mm. in diameter; nutlets usually 4. 



2. C. ricularis. 

 Leaf-blades broad, rhombic, lobed and incised. 3. C. erythropoda. 



Inflorescence pubescent; spines short and stout; leaf-blades broad, ovate or obovate, 

 somewhat lobed above the middle. 4. C. Douglasii. 



Fruit red or red-purple; leaves pubescent beneath, at least on the veins. 

 Teeth of the leaves not glandxxlar; nutlets deeply pitted on the faces. 



5. C. succulenta. 

 Teeth of the leaves glandular; nutlets not pitted. 



Leaf-blades suborbicular. 6. C. chrysocarpa. 



Leaf-blades ovate, oval or obovate, more or less cuneate at the base. 



Leaf-bladesmostly5-9cm. long, with shallow, acute lobes. 7. C. IVilliamsii. 

 Leaf-blades 2-6 cm. long, with deep, often acuminate lobes. 



8. C. Columbiana. 



Family 62. AMYGDALACEAE. Plum Family. 



Drupe with pulpv exocarp; leaves not fascicled. 1. Pruxus. 



Drupe with almost dry exocarp, pubescent; leaves fascicled. 2. Emplectocladus. 



1. PRUNUS L. Plums, Cherries. 



Flowers few, umbellate or corymbose. 



Fruit with a ventral groove and flat stone. (Plttms.) 



Leaves oval or orbicular, rounded at the apex. 1. P. subcordata. 



Leaves lanceolate to obovate, acute or acuminate. 



Trees or slu-ubs, usually spiny; leaves serrate to near the base. 



2. P. americana. 

 Low undershrub, unarmed; leaves entire at the base. 3. P. prunella. 



Fruit without a ventral groove; stone subglobose. (CHERRIES.) 



Creeping shrub: flowers umbellate. 4. P. Besseyi. 



Erect shrubs or trees. 



Hypanthium decidedly obconic; flowers umbellate from naked lateral buds. 



5. P. Ignota. 

 HM>ant Ilium campanulate or turbinate; flowers more or less corymbose. 

 Leaves acute, serrate. 



Corvmbs naked. 6. P. pennsylramca. 



Corymb usually subtended by 1 or 2 leaves. 7. P. corymbulosa. 



Leaves obtuse or roimded at the apex, crenulate. 



Leaves glabrous. 8. P. emarpinata. 



Leaves pubescent. 9. P. prunifolia. 



Flowers many, racemose on leafy branches. (Choke Cherries.) 



Leaves more or less pubescent beneath. , ., , , . , 



Peduncles stout; pedicels pubescent, shorter than the frmt, deciduous; leaves thick. 



10. P. vahda. 



