Trees , 9--18 m; trunks usually 1, branching mostly deliquescent, trunk and branches terete. Bark of trunk and branches brownish gray to light brown, thin, smooth, breaking and shredding into shaggy vertical strips and scales; lenticels generally inconspicuous. Wood nearly white to light brown, very hard and heavy, texture fine. Branches, branchlets, and twigs conspicuously 2-ranked; young twigs differentiated into long and short shoots. Winter buds sessile, ovoid, somewhat laterally compressed, apex acute; scales many, imbricate, longitudinally striate. Leaves on long and short shoots, 2-ranked. Leaf blade narrowly ovate to ovate, elliptic, or obovate with 10 or more pairs of lateral veins, 2.5--13 × 1.5--6 cm, thin, margins doubly serrate to serrulate; surfaces abaxially glabrous to tomentose. Inflorescences: staminate catkins terminal on branches, mostly in small, racemose clusters, formed previous growing season and exposed during winter, expanding with leaves; pistillate catkins proximal to staminate on short, lateral, leafy new growth, solitary, ± erect, elongate, bracts and flowers uncrowded. Staminate flowers in catkins 3 per bract, crowded together on pilose receptacle; stamens 3(--6), short; filaments often divided part way to base; anthers divided into 2 parts, each 1-locular, apex pilose. Pistillate flowers 2 per bract. Infructescences loosely imbricate, strobiloid clusters of closed inflated bracts; clusters pendulous, elongate; bracts deciduous with fruit, inflated, bladderlike, each bract enclosing 1 fruit. Fruits small nutlets, ovoid, longitudinally ribbed, often crowned with persistent sepals and styles. x = 8.
More
Trees deciduous; bark scaly, rough. Buds ovoid, with many overlapping scales. Leaves irregularly and doubly serrate, sometimes lobulate. Male inflorescence pendulous, clustered at apex of branchlets, slender, naked during winter; bracts overlapping, each subtending 1 flower; perianth absent; stamens 3-14; filaments 2-cleft at apex, inserted at base of bracts; anthers each with 2 separate locules, pubescent at apex. Female inflorescence terminal, racemose; flowers paired; bracts overlapping, saccate, inflated, membranous, with reticulate veins and rigid hairs at base, usually lobed at apex; calyx adnate to ovary. Nutlet narrowly oblong, narrowly ovoid, ovoid-ellipsoid, or obovoid, ribbed, completely enclosed in bracts.
Staminate catkins dense, the spirally arranged, depressed-ovate scales each terminating in a sharp point and subtending a cluster of several stamens without perianth; filaments short, divided at the summit, each branch bearing an apically pilose half-anther; pistillate catkins slender, loosely fld, the ovate, hairy bracts caducous, subtending 2 fls each enclosed within an ovoid pouch composed of united bract and bractlets, the cal minute; bracts accrescent and inflated in fr, forming a hops-like strobilus; fr a flattened-ovoid nutlet; trees or tall shrubs with rough, flaky bark, the catkins opening with the lvs in the spring. 10, mainly N. Temp.
Home
