June until frost. According to W. J. Shephard there are in the interior of British Columbia hundreds of acres of spreading dogbane (A. androsaemifolium). It is the source of a large quantity of honey in dry seasons and in districts where there is not a large amount of rain. The pinkish white bell-shaped flowers have a pleasant odor, and remain in bloom for a long time. The honey is very white, like that of fireweed, but it is usually more dense and has a better flavor. In 1922 there was a very large yield of honey from this source.
DOGWOOD (Cornus). — Shrubs with small white flowers in flat-topped clusters. There are about 18 species in America north of Mexico. They are not usually common enough to he of much value, but at Divide, West Virginia, the hillsides are in spring white with the bloom, which is frequently visited by honeybees. Nectar is secreted in a thin layer by a ring at the base of the style. Also called cornel.
DROUGHTWEED. — See Turkey Mullein.
DUTCH CLOVER. — See White Clover.
ELDERBERRY. — See Pollen Flowers.
EPHEDRA (Ephedra antisyphilitica). — Also called Mexican ground pine, “buchu,” and switch plant. A low straggling shrub, 1 to 4 feet tall, growing on mesas and dry hills in the semiarid regions of New Mexico, western Texas, and Mexico. The leaves are reduced to two small, dry, thin, nearly transparent scales at the joints of the stems. The older stems are woody and light gray in color; the young stems are hollow, long-jointed, striate, about the size and length of a knitting-needle. They are green in color and perform the function of leaves. The small flowers are in little clusters, and are unisexual. At Robert Lee, Coke County, Texas, it blooms in February and March, and yields a large amount of pollen and nectar, strongly stimulating brood-rearing. A snow-fall of several inches only temporarily interrupted the nectar flow. In this locality it flourishes on rocky hills, where it attains a height of about two feet. Three other species of Ephedra occur in New Mexico and the other southwestern states, where they are probably of some importance to beekeeping. The young stems of these plants strongly resemble those of the horsetails. This is a very unique genus of honey plants, since it belongs to the Gymnosperms.
ERYNGO. — See Blue Thistle.
EUCALYPTUS. — A large genus of evergreen trees growing chiefly in the coast regions of Australia and New Guinea. About 150 species have been described, of which not far from 100 have been introduced into California. At the Forestry Station at Santa Monica there have been planted nearly 70 species and varieties, the qualities of which are being tested and compared. In the groves in the Berkeley Hills, Alameda County, there are from 1500 to 2000 acres, and another large center is around Newark. To a much smaller extent they have been planted in Arizona and the Gulf region of Texas. Few Eucalypti will endure a temperature below 20 degrees, or above 120 degrees F. They grow very rapidly, and a few species may become very valuable sources of timber and other commercial products; and all are very effective as avenue and landscape trees. Some of the species are popularly known as gum-trees because a resinous gum flows from incisions in the bark; others are called iron-bark trees, from their very hard bark; and still others, from their fibrous bark, are termed stringy-bark trees. To this genus belongs the tallest tree in the world, E. amydalina, which attains the height of 480 feet. (Fig. 55.)
The Eucalypti, popularly called “gum-trees,” from which the honey crop of Australia is chiefly obtained, yield a large amount of nectar. The blooming-time of the various species in California varies so widely that there are at least from three to seven species in flower during every month of the year, and a species may bloom twice in the same year.
In Australia a part of the species bloom very irregularly, as white box gives a flow of nectar in some seasons during May, June, July, and August; yellow box in