336 FOREST TREES OF THE PACIFIC SLOPE. 



Climatic Conditions. — Similar to those of Fremont cottonwood. 



Tolerance. — Endures but little shade at any age. 



Reproduction. — Moderately prolific seeder. Seed of fairly high rate of germfcation 

 (often tardy), and of persistent vitality. Reproduction scanty; mainly and best on moist 

 or wet exposed sand or gravel. Dependence upon constant soil moisture (available only 

 near stream beds) and occurrence of heavy seasonal flood waters where seed is dropped 

 doubtless limit reproduction. 



Family ROSACE-ffi. 



The Rosacea? are a very large family of trees, shrubs, and herbs of world- 

 wide distribution. Among them are some of the most important timber, fruit, 

 and ornamental trees, including cherries, plums, apples, pears, quinces, and haw- 

 thorns, as well as innumerable shrubs and herbs, such as roses, etc. Prac- 

 tically only one forest tree species (black cherry), represented in eastern United 

 States, is of commercial use. All of the other trees of the family belonging 

 to our forests are shrubby and of little or no economic use ; some of them are, 

 however, important for the sturdy cover they form on dry, scantily clothed 

 montain slopes. 



Representatives of the family treated here have showy, perfect flowers 

 (with male and female reproductive organs in each blosssom). The flowers 

 open in spring or summer and the fruit is ripened the same season. A point of 

 resemblance in the flowers is the cluster of thread-like, bead-tipped, pollen- 

 bearing bodies (stamens) in the center of each blossom. (Compare the blooms 

 of garden cherries, plums, peaches, etc.) Fruits of some of these trees, such 

 as cherries and plums, are edible and well known, and are characterized by their 

 juicy sweet or tart (in some species very bitter or astringent) pulp, which 

 covers a hard-shelled, round or flat seed. Other groups of this family, "haws" 

 and "crab-apples," have small, mealy, or hard-fleshed fruits resembling minia- 

 ture apples, with very small, bony, rough, thick-shelled seeds, or smooth, thin- 

 shelled seeds. The mountain " mahoganies," of this family, have dry fruits, 

 which are very different in appearance from any of the others, but which are 

 structurally related. Since the fruits of many rosaceous trees are usually lus- 

 cious, they are extensively eaten (without injury to the vitality of the seeds) by 

 birds and mammals, by which the seeds are principally disseminated. The 

 dry fruits of mountain mahoganies have special hairy attachments, by the aid 

 of which they are wafted far from the mother trees by the wind. The leaves, 

 evergreen or shed every autumn, occur singly on the twigs — never in pairs, 

 one opposite another. 



CERCOCARPTJS. MOUNTAIN MAHOGANIES. 



Mountain mahoganies are a small group of shrubby trees which derive their 

 name from their red-brown, mahogany-colored wood, which is exceedingly heavy, 

 fine-grained, dense, and hard. They are much-branched, usually crooked, scaly- 

 barked trees with stiff branches which have peculiar, short, spine-like twigs, and 

 very small, thick, evergreen leaves. When bruised, the leaves give off a resinous 

 odor. The fruit, a long-tailed, hairy, seed-like body, is inclosed in a small, 

 striped tube (part of the flower). When ripe it escapes and is blown for consid- 

 erable distances by the wind. Occasionally it is dislodged by grazing animals 

 and carried away in their hairy coats. ■ 



Of little or no economic use for their wood, but of some importance for 

 the strong, though open and scanty, cover the trees form on the driest and most 

 exposed of high mountain slopes. Three species inhabit the arid sections of the 

 western United States and adjacent portions of Mexico, to the dry soil and cli- 

 matic conditions of which they seem specially adapted. 



