Dioecious or rarely bisexual trees and shrubs. Leaves alternate or rarely subopposite, entire or serrulate, teeth usually gland-tipped, pinnately-veined,sometimes palmately 3-5 veined at base, deciduous. Stipules free, usually small, deciduous, scale- like, rarely leafy. Flowers in erect or pendulous spikes or racemes (catkins). Catkins often sericeous or villous at least at first, terminal on short leafy lateral shoots or sessile, axillary. Flowers solitary in the axil of a membranous, deciduous or persistent bract. Perianth absent except for disc. Disc flat or cup-like or consisting of 2 glandular scales, anterior and posterior, or sometimes one side (posterior). Male flowers with 2-many stamens; filaments free or united. Females flowers with ovary solitary, sessile or shortly stipitate, 1- 1 ocular; style short or very short, 2-branched, branches sometimes bifid; ovules numerous, parietal. Capsules ovoid,2-4 valved. Seeds few or numerous, small, oblong, each with a tuft of long straight hairs.
Dioecious trees or shrubs with erect or prostrate stems, sometimes with short ascending shoots, stems usually pubescent or silky villous at first, indumentum persistent or not on two- year old branchlets. Leaves alternate or rarely sub opposite, elongate or short and narrowly or broadly elliptic or obovate; margins entire or glandular-serrulate, rarely deeply toothed; venation pinnate throughout, stipules usually present,minute,or ovate and semicordate, generally more strongly developed and more persistent on leading shoots. Flowers few or numerous in erect or pendulous, sessile or pedunculate catkins, peduncles bearing 1 or 2 small or minute glands at base. Male flowers usually with 2, sometimes 1, rarely 6-12 stamens. Female flowers with style bifid, sometimes deeply, branches simple or bifid. Capsule 2-valved.
Tree 4-20m, branches pendulous; bark glabrous, brown, glossy. Leaves stem apex narrowly elliptic or linear- lanceolate, 4.5-9 x 0.7-1.5cm, acuminate, base cuneate, margins regularly serrulate, glabrous; petioles 5-7mm. Catkins precocious, peduncles bearing a few small, entire- margined leaves 1-2cm. Male catkins sub sessile or on peduncles 2-6mm, suberect, 2-3 x 0.5cm; rachis tomentose; bracts oblong, 1.5mm, pale, glabrous or villous within; stamens 2, filaments free, pubescent at base. Female catkins on peduncles 5-10mm, 2-3 x 0.5cm; bracts lanceolate, otherwise similar to male. Capsules ovoid, 2.5mm,villous, sessile; style short, shortly 4-lobed at apex.