SALICACEAE

WILLOW FAMILY

Shrub, tree, generally dioecious (rarely monoecious)
Stem: trunk < 40 m; wood soft; bark smooth, bitter; buds scaly
Leaves simple, alternate, deciduous; stipules generally deciduous, often large
Inflorescence: catkin, generally appearing before leaves; each flower subtended by disk or 1–2 nectary glands and 1 bract
Flower: perianth 0
Staminate flower: stamens 1–many
Pistillate flower: pistil 1, ovary superior, chamber 1, stigma lobes 2–4
Seeds many; hairs fine, white, cottony
Fruit: capsule; valves 2–4
Genera in family: 2 genera, 340 species: generally temp (except Australia, Malay Archipelago) moist places; many cultivated. Hybridization common; identification often difficult. Family description, key to genera by John O. Sawyer, Jr.

SALIX

WILLOW

George W. Argus

Shrub, tree, dioecious; bud scale 1, not sticky, margins generally fused (or free, overlapping)
Stem: twigs generally flexible and not glaucous
Leaf: blade linear to widely obovate, entire to toothed, generally ± hairy
Inflorescence: dense catkin emerging before, with, or after leaves, sessile or on a short leafy shoot; bract subtending each flower
Flower: perianth 0
Staminate flower: stamens 1–8
Pistillate flower: ovary stalked or sessile, style 1 or 0, stigmas 2, each sometimes 2-lobed; nectaries 1–several, generally rod-like, generally between inflorescence axis and flower
Fruit: valves 2
Species in genus: ± 400 species: ± worldwide, especially n temp, arctic
Etymology: (Latin: ancient name)
Reference: [Argus 1986 Syst Bot Monog 9:1–170; Dorn 1976 Canad J Bot 54:2769–2789]
Difficult, highly variable. Not all specimens will key easily; sprout shoots and other extreme forms are not included in keys, may require field comparison for identification. Studies of variation, hybridization needed.

Native

S. sitchensis Bong.

SITKA WILLOW

Shrub, small tree, < 7 m
Stem: twigs brownish, silky or long-soft-wavy-hairy, flexible or ± brittle at base
Leaves: young leaves hairy; mature blade 52–110 mm, lanceolate to widely obovate, acute or pointed (base wedge-shaped), entire to finely serrate, strongly rolled under near base, lower surface not glaucous, densely short-silky to densely silky-woolly and generally obscured, upper surface dark green, becoming glabrous
Inflorescence appearing just before or with leaves, 26–95 mm, on leafy shoots 3–20 mm, rarely sessile; flower bract tawny or brown
Staminate flower: stamen 1
Pistillate flower: ovary silky, widely ovoid, style 0.4–0.8 mm, stalk 0.4–1.2 mm
Chromosomes: 2n=38
Ecology: Common. Tidal swamps, marshes, springs, streambeds
Elevation: 0–400 m (1800–2500 m in Siskiyou, Humboldt cos.).
Bioregional distribution: Northwestern California, Central Western California, (except Inner South Coast Ranges), w Western Transverse Ranges
Distribution outside California: to Alaska, Montana
Synonyms: S. coulteri Andersson
Horticultural information: WET: 1, 2, 4, 5, 6, 7, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; STBL.