plant, ranging from British Columbia to northern Idaho and northern Cali- 

 fornia, is by far the most abundant and widely distributed of the Pacific 

 coast species of blackberry. It grows principally on the coastal side of the 

 Cascade Mountains, but also extends over the summit to the eastern slope, 

 where it is confined chiefly to canyon bottoms and moist timbered areas on 

 which site conditions are similar to those prevailing on the west side. This 

 plant is largely replaced in California by a closely related species, California 

 dewberry (R. ursinus, listed by some authors as R. vitifolius). 



Trailing blackberry grows most profusely in cut-over areas and old burns, 

 but also appears commonly in open woods, old fields, and clearings, and along 

 roadsides and fence rows, ranging from sea level to elevations of about 

 5,000 feet. It is often found in the virgin Douglas fir forests, although it 

 usually does not thrive under dense shade. The cutting and removal of the 

 timber stands and the subsequent broadcast slash burns result in practical 

 elimination of certain species of the original forest and the suppression of 

 other species, due to changes in light, temperature and moisture. However, the 

 profound ecological changes attendant on logging favor the production of trail- 

 ing blackberry ; this species together with fireweed and bracken fern are the 

 principal species to take early possession of the land after cutting and broad- 

 cast burning. 1 If the burn is not too severe, the tangled cane growth of trailing 

 blackberry often comprises a principal part of the vegetation for a few years, 

 but gradually disappears as other shrubs and conifer seedlings shade it out 



The extensive cut-over areas in western Washington and Oregon ordinarily 

 produce an abundance of palatable forage during the early stages of plant 

 succession, and large-scale livestock operations are frequently conducted on this 

 temporary ground cover. Under such conditions, trailing blackberry is an 

 important forage plant. The palatability of the leafage is generally fairly 

 good to good for sheep and fair for cattle. In studying grazing use on Douglas 

 fir cut-over lands in Washington, the late Douglas C. Ingram J found that 

 utilization of the herbage of trailing blackberry varied from 26 percent on the 

 moderately grazed areas to 91 percent on the heavily utilized portions of the 

 range, with averages of 58 and 62 percent, respectively, during 2 successive 

 years. Deer and elk graze the leaves with moderate relish ; deer are excep- 

 tionally fond of the ripe berries. The fruit is likewise a favorite food of 

 bear and smaller animals as well as of grouse, quail, and other birds. 



Numerous horticultural varieties of blackberries and dewberries have been 

 developed from trailing blackberry. 23 Among the outstanding varieties devel- 

 oped from this species are Belle of Washington, Cazadero, Skagit Chief. 

 Washington Climbing, and probably Humboldt. 



Trailing blackberry is one of several species of Rubus having two kinds of flowers, 

 male (staminate) and female (pistillate), each kind generally being borne on separate 

 plants. The male flowers, having petals up to about 1 inch long, are much larger and 

 showier than the female flowers. The specific name macropetalus is an adjective mean- 

 ing long-petaled (Greek macros, long, and petalon, petal) and refers to the prominent 

 petals. This species is variable in the form of the leaves and hairiness anil prickliness 

 of stems, but apparently is distinct except as it merges into California dewberry. 



California dewberry (R. ursi'nus) closely resembles trailing blackberry. It 

 differs mainly in its thicker, more hairy, and less sharply and deeply toothed 

 leaves, with a pronounced tendency toward simple or three-lobed leaves. More- 

 over the stems, sepals, and flower stalks are more hairy but less glandular. 

 California dewberry is a very common plant in the valleys and foothills at 

 low altitudes, growing chiefly along streams or in springy flats from southern 

 Oregon to Lower California. Some botanists prefer to use the older name, 

 R. vitifolim, for this species, but according to Bailey, 2 the identity of the 

 plant described as R. mtifolins is unknown. This species is of minor im- 

 portance as a forage plant. Like trailing blackberry, it is prized for its fruit 

 and has been the source of several varieties of cultivated blackberries. 



1 Ingram, D. C. VEGETATIVE CHANGES AND GRAZING USE ON DOUGLAS FIR CUT-OVER LAND. 

 Jour. Agr. Research [U. S.] 43 : 387--H7, illus. 1931. 



2 Bailey, L. H. THE BLACKBERRIKS OF NORTH AMERICA. Gentes Herbarum 2(6): 

 [271]-423, illus. 1932. 



3 Darrow, G. M., and Longley, A. E. CYTOLOGY AND BREEDING OF RUBUS MACROPETALUS, 

 THE LOGAN, AND RELATED BLACKBERRIES. Jour. Agr. Research [U. S. ] 47:315330, illus. 

 1933. 



