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. ligulifolia (C.R. Ball) C.R. Ball

STRAP-LEAFED WILLOW

Shrub < 8 m
Stem: twigs brownish, glabrous or long-shaggy-hairy
Leaves: stipule tip acute; young leaves glabrous or hairy; mature blade 60–133 mm, lanceolate to elliptic, acuminate (base acute to rounded or cordate on vigorous leaves), margin gland-dotted to serrate, surfaces glabrous or sparsely long-soft-wavy-hairy, lower surface glaucous
Inflorescence appearing with or just before leaves, 12–38 mm, sessile or on leafy shoots < 5 mm; flower bract brown, hairs curly
Staminate flower: stamens 2
Pistillate flower: ovary glabrous, style 0.2–0.6 mm, stalk 0.9–2.5 mm
Chromosomes: 2n=38
Ecology: Rocky streams
Elevation: 1100–2500 m.
Bioregional distribution: High Cascade Range, High Sierra Nevada, Warner Mountains
Distribution outside California: to Idaho, Wyoming, New Mexico
Lf margins often incorrectly called "entire"
Horticultural information: TRY; STBL.