AMYGDALACEAE . 1 39 



18. Thorns 1 to l^i inches long; midrib yellow 



C. assurgens Sarg. 



18. Thorns up to 2\^ inches long. 



19. Midrib greenish; petioles up to 11/2 inches 

 long; fruit obovoid, crimson, pale dotted 



C. Hillii Sarg, 



19. Midrib yellow; petioles l^i to 3 inches long; 

 fruit subglobose, bright red, pale dotted 



C. sertata Sarg. 



17. Cal)r£ much enlarged on the fruit 



C. coccinioides Ashe 



16. Mature leaves pubescent or tementose below (fig. 



32) C. mollis (T. & G.) Scheele 



A, Leaf veins extending both to lobe points and to sinuses. 

 E. Leaves triangular-ovate; sepals deciduous (fig. 32) 



C. Phaenopyrum (L. f.) Med. 



E. Leaf bases cuneate ; sepals persistent. 



20. Leaves with 3 to 5 short, broad, serrulate lobes 



C. Oxyacantha L. 



20. Leaves with 3 to 7 long, narrow, entire lobes 



C. monogyna Jacq. 



AMYGDALACEAE 

 The Plum Family 



The plum family consists of trees or shrubs which bear al- 

 ternate, simple leaves, deciduous stipules and, in the American 

 species, perfect flowers that have 5 sepals, 5 petals and 10 or 

 more stamens. The pistils are usually solitary and develop into 

 a single-seeded fruit known as a drupe, of which the plum is 

 typical. 



The family is widely distributed in the north temperate zone 

 and contains some 120 species, divided into about 10 genera. 

 Among the important species are the edible and cultivated 

 plums, the peach, the apricot and the cherries. The family is 

 represented In Illinois by both native tree and shrub forms. 



PRUNUS (Tournefort) Linnaeus 

 Plums and Cherries 



These are shrubs or trees with alternate, deciduous leaves 

 which usually are toothed on the margin and can be definitely 

 recognized by the presence of glands on the petioles near the 

 base of the leaf blades. The flowers, which are perfect, are 

 solitary, umbellate, or in corymbs at the end of leafy branches, 



