A shrub of the same habit as C. avellana, but more robust, sometimes a tree 20 ft or more high; young shoots glandular-hairy. Leaves broadly obovate or roundish, heart-shaped at the base, usually with a short, slender, abrupt point; toothed all round the margin, doubly so on the upper half; 2 to 5 in. long, 11⁄2 to 4 in. wide; stalk glandular, 1⁄4 to 1⁄2 in. long. Male catkins 2 to 3 in. long. Nut ovate-oblong; the husk nearly twice the length of the nut, cut into numerous deep, narrow lobes.
Native of S. Europe, but not of Britain; introduced in 1759. It is the parent of the filberts of English orchards, distinguished from the hazel or cobnut by the husk protruding well beyond the nut, and quite enclosing and holding it. The nut itself is also longer and proportionately narrower. Several varieties are cultivated for their nuts, but the only one of an ornamental character worth mentioning is
cv. ‘Purpurea’, whose leaves are of a dark purple. One of the most robust and effective shrubs of this colour. The catkins also are purple. Bot. Mag., n.s., t. 268.