Corylus (ancient Greek name). Cupuliferae, tribe Betuldceae. Hazel. Filbert. Cobnut. Shrubs, rarely trees : lvs. alternate, deciduous, stipulate, petioled, serrate and more or less pubescent: fls. monoecious, appearing before the lvs., staminate, in long, pendulous catkins, formed the previous year, and remaining naked during the winter (Fig. 560), each bract bearing 4 divided stamens; pistillate included in a small, scaly bud with only the red styles protruding (Fig. 561): fr. a nut, included or surrounded by a leafy involucre, usually in clusters at the end of short branches. Eleven species in N. Amer., Eu. and Asia are described. Numerous varieties are cult. in Eu. for their edible nuts. They are also valuable for planting shrubberies, and thrive in almost any soil. Prop. by seeds sown in fall, or stratified and sown in spring; the varieties usually by suckers, or by layers, put down in fall or spring; they will be rooted the following fall. Budding in summer is some times practiced for growing standard trees, and grafting in spring in the greenhouse for scarce varieties. They may also be increased by cuttings of mature wood taken
off in fall, kept during the winter in sand or moss in a cellar and planted in spring in a warm and sandy soil. Illustrated monograph of the cultivated varieties by Franz Goescbke, Die Haselnuss (1887). See, also, bulletin on Nut-culture by the U.S. Dept. of Agr.

A. Husk or involucre consisting of two distinct bracts
(sometimes partly connate).
B. Involucre deeply divided into many linear, nearly entire segments, densely beset with glandular hairs. Tree.

Colurna, Linn. Tree, to 70 ft.: lvs. deeply cordate, roundish ovate to ovate-oblong, slightly lobed and doubly crenate-serrate, at length nearly glabrous above, pubescent beneath, 3-7 in. long: nut roundish ovate, 4-5 in.long. From S. Himal.—Ornamental tree, with regular pyramidal-head, not quite hardy north. Rarely cult. for the fr. under the name of Filbert of Constantinople or Constantinople nut.

B. Involucre sparingly glandular, with lanceolate or triangular-dentate lobes: nut slightly compressed. Shrubs.

Americana, Walt. Fig. 562. Shrub, 3-8 ft.: lvs. slightly cordate or rounded at the base. broadly ovate or oval, irregularly serrate, sparingly pubescent above, finely tomentose beneath, 3-6 in. long: involucre com pressed, exceeding the nut, the 2 bracts sometimes more or less connate, with rather short, irregular, toothed lobes: nut roundish ovate, about 1/2 in. high. From Canada to Fla. west to Ontario and Dak. B.B. 1:507. Two forms of involucre are shown in Fig. 562. This figure is adapted from the bulletin of the Dept. of Agr. on Nut-culture.

Avellana, Linn. Figs. 560, 562. Shrub,to 15 ft.: lvs. slightly cordate, roundish oval or broadly obovate, doubly serrate and often slightly lobed, at length nearly glabrous above, pubescent on the veins beneath: involucre shorter than the nut, deeply and irregularly incised: nut roundish ovate, 1/2-3/4 in. high. Eu., N. Afr., W. Asia.—Var. aurea, Hort. Lvs. yellow. Var. laciniata, Hort. (var. heterophylla, Loud.). Lvs. laciniately incised or lobed. Var. pendula, Hort. With pendulous branches. There are also many varieties cultivated for their fruit.

AA. Husk tubular, of connate bracts.
B. Involucre campanulate, with large, dentate, spreading lobes.