ROSACEAE 



The Cherries, Plums, and Peaches 

 Characteristics of the Genus Prunus L. 



HABIT. Shrubs or usually small trees, only a few species reach- 

 ing sizes of commercial importance. 



LEAVES. Alternate; simple; deciduous or persistent; usually 

 serrate, rarely entire; stipules free from petiole, early deciduous; 

 petiolate. 



FLOWERS. Regular; perfect or rarely dioecious; solitary 

 or in terminal or axillary racemes, corymbs, or umbels; ap- 

 pearing from separate buds with, before, or after leaves; calyx 

 5-lobed, tubular; corolla 5-petaled, usually white, deciduous, 

 stamens usually 15-20; ovary inserted in bottom of calyx tube, 

 inferior or superior, 1 -celled, 2-ovuled. 



FRUIT. Thin dry, or thick fleshy, 1 -seeded drupe; stone 

 bony, smooth, or rugose; indehiscent; important as food in 

 several species. Seed: filling cavity of nut, suspended, thin- 

 coated, pale brown. 



TWIGS. Slender or stout; round; astringent; red to brown; 

 marked by lenticles and usually by small, elevated, horizontal 

 leaf scars. Winter buds: terminal present or absent, lateral 

 nearly equal in size, scales imbricated and the inner accrescent 

 and often colored, 



BARK. Astringent; gray to dark brown; plated or scaly. 



WOOD, From light to heavy and hard; fine-textured; diffuse- 

 porous; durable; heartwood light or dark brown, often reddish; 

 sapwood lighter colored; a few species are important timber 

 trees, 



GENERAL. About 30 species of Prunus are native to North 

 America, 18 of these being arborescent at times. Seven intro- 

 duced species, four of which are highly important fruit trees, 

 have become naturalized in various parts of the United States 

 and Canada. These species, which are included in the key are: 

 P. avium (L.) L., Mazzard cherry; P. cerasus L., sour cherry; 

 P. domestica L., garden plum; P. insititia L., Damson plum; 

 P. mahaleb L., Mahaleb cherry; P. persica (L.) Batsch., peach; 

 and P. spinosa L., sloe or blackthorn. The almond, P. amyg- 

 dalus Batsch,, and the apricot, P. armeniaca L., while not natural- 

 ized, are commonly planted in warmer regions. As with other 

 cultivated fruits, these have been improved until there are numer- 

 ous forms or varieties. The commonly planted ornamental 

 flowering almond, P. triloba Lindl., is a shrub or small tree. 



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