22 HOUGH'S AMERICAN WOODS. 



light greenish yellow sap-wood. Specific Gravity, 0.7333 ; Percentage of 

 Ash t 0.51; Relative Approximate Fuel Value, 0.729G; Coefficient of 

 Elasticity, 129238 ; Modulus of Rupture, 1273 ; Resistance to Longi- 

 tudinal Pressure, 694 ; Resistance to Indentation, 258 ; Weight of a 

 Cubic Foot in Pounds, 45.70. 



USES. The wood of this tree is valuable for posts, tree-nails, in turn- 

 ery and for the ribs of vessels, though of late the operations of a locust- 

 borer greatly curtails its use. The early popularity of the tree for 

 ornamental purposes is attested by the numerous individuals we find 

 now standing about old country dwellings and along fences. It is said 

 to be more extensively introduced into Europe than any other American 

 tree for ornamental purposes. 



The bees gather much honey from this tree while in blossom. 



MEDICINAL PROPERTIES. The bark of the root of this tree is said to 

 possess tonic properties and in large doses purgative and emetic.* 



ORDER ROSACE.2E : ROSE FAMILY. 



Leaves alternate and with stipules which sometimes fall early or are rarely want- 

 ing. Flowers regular ; sepals 5 or rarely fewer, united at the base and often fur- 

 nished outside with bractlets resembling the sepals ; petals as many as the sepals 

 or rarely wanting, distinct and inserted on a disk which lines the calyx-tube ; stamens 

 distinct, numerous (with rare exceptions) and inserted with the petals on the disk of 

 the calyx-tube ; pistils 1-many distinct or united and often combined with the calyx- 

 tube. Fruit various, as drupe, pome, achenium, etc. ; seeds solitary or few, mostly 

 albumenless, with straight embryo and large thick cotyledons. 



Trees, shrubs and herbs many of great economic value in the production of most 

 useful fruits, beautiful flowers, choice perfumes, etc. 



GENUS PRUNTJS, TOURN. 



Leaves simple ; stipules free and commonly deciduous. Flowers perfect, with 

 calyx regular, free and falling away after flowering; petals widely spreading; stamens 

 15-30 ; pistil solitary with style terminal or nearly so and ovary containing 2 pendu- 

 lous ovules. Fruit a drupe, fleshy with a smooth 1 -seeded (rarely 2-seeded) stone. 



Trees, and shrubs. (Prunus is the ancient Latin name of the plum-tree.) 



81. PRUNUS NIGRA, AIT. 

 CANADA PLUM, WILD PLUM. 



Ger., Ganadische Pflaume ; Fr., Prunellier de Canada : Sp., Ciruelo de 



Canada. 



SPECIFIC CHARACTERS: Leaves obovate or broadly ovate-oblong, abruptly narrow- 

 ing to a long-pointed apex, varying from wedge-shape to slightly heart-shape at base, 

 3 to 5 in. long, doubly crenate- serrate, with glandular teeth, membranous, and with 

 light-green under surfaces, the pale mid-rib and veins conspicuously prominent, con- 

 duplicate in vernation; petioles short, stout, reddish above, and furnished near the 

 blade with two to four glands; stipules linear, sometimes cut-lobed, glandular- 

 serrate. Flowers appear before the leaves, about 1 in. across, in 3-4- flowered 



* U. S. Dispensatory, 16th ed., p. 1907. 



