FOEEST TREES OF THE PACIFIC SLOPE. 431 



5 to 10 inches long. They remain on the twigs more or less during the winter. 

 gradually splitting open and liberating their small, flat, fringe-winged seeds 



(fig. 205, b), which are light and easily watted by the wind, the principal agent 

 of dissemination. The pods, which contain a very large number of seeds closely 

 resembling catalpa seeds, have a flat central partition running their entire 

 length, and upon two sides of which, as in catalpa pods, the seeds are borne. 

 Wood, very much like that of catalpa in color and structure, is light and soft, 

 yellowish brown, frequently with yellow areas, and durable in contact with the 

 ground. Not used for commercial purposes, but sometimes locally used for 

 fence posts, for which it is highly prized on account of its durability in the 

 ground. 



Longevity. — Not fully determined. Record of one tree 8§ inches in diameter 

 shows an age of 43 years. Maturity is probably reached in less than 50 years. 

 Old trees grow persistently for a long time, but show they have passed maturity 

 by their hollow old trunks. 



RANGE. 



Through southwestern (from near Laredo) and western Texas, southern New Mexico, 

 Arizona, southern Utah and Nevada, and southern California (San Diego County i; 

 northern Mexico. 



OCCURRENCE. 



Borders of desert and low mountain water courses, moist sinks, and water holes, in 

 rather dry, well-drained, sandy and gravelly soils. Scattered and in groups. 

 Climatic Conditions. — Similar to those of mesquites. 

 Tolerance.— Intolerant of shade. 

 Reproduction and seeding habits undetermined. 



Family RTJBIACEJE. 



Rubiacese is popularly known as the madder family, to which belong the 

 world-famous madder plants of India and of the Mediterranean country, whose 

 roots yield the most permanent red dyes known. Other important representa- 

 tives are the coffee and cinchona trees of South America, the latter yielding the 

 alkaloid tonic drugs cinchonidia and quinine, so much used in medicine. The 

 family comprises shrubs, trees, and herbs of some 3.j0 genera, natives mainly 

 of tropical countries. Four genera, containing trees and shrubs, are represented 

 in the United States by arborescent species. One of these. Oephalanthus, occurs 

 from the Atlantic to the Pacific. 



OEPHALANTHUS. 



Cephnlanthus forms a small group of unimportant species, one of which in- 

 habits the Pacific region, extending also throughout the eastern United States. 

 Characters of the genus are given under its one widely distributed specie-. 



Button Bush. 



Cephalanthus occidentalis Linnaeus. 



DISTIM.l IsniM, CHARACTERISTICS. 



Perhaps no woody plant is more widely known as a common shrub forming 

 thickets on the borders of swamps, ponds, and streams thai: button bush. It has 

 been known since the seventeenth century. Put not until comparatively recent 

 years has it been found to attain tree size, as in parts of southern Arkansas, 

 eastern Texas, and at a few stat ions in < California. Tree tonus may be discovered 

 at other points, in this form it is from _'<• to 30 ivd high, with a clear, straight 

 trunk of 10 or 15 feet in length, and from 6 to s inches in diameter; taller and 



