Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

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.

POPULUS

POPLAR, COTTONWOOD, ASPEN

John O. Sawyer, Jr.

Tree
Stem: trunk < 40 m; young bark smooth, pale yellow-green to gray; older bark furrowed, brown to gray; twigs with swellings below leaf scars; winter bud generally resinous, scales > 3
Leaves generally glabrous (juvenile leaves may differ from adult leaves); blade 3–11 cm, elliptic to triangular, veins pinnate or subpalmate, tip generally elongate
Inflorescence: catkin pendent, 3–8 cm; bract cut into narrow segments; flowers sessile, on a cup- or saucer-like disk
Staminate flower: stamens 8–60
Pistillate flower: style short, stigmas 2–3(4), large, scalloped to 2-lobed
Fruit spheric to conic; valves 2–3(4), 3–12 mm
Species in genus: 40 species: n hemisphere
Etymology: (Latin: name for plants of this genus)

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