Jepson Interchange (more information)
Print edition is available from the University of California Press
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This page is based on the 1993 Jepson Manual.
Please see the Jepson eFlora for up-to-date information about California vascular plants. |
| Jepson Flora Project: Jepson Interchange |
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TREATMENT FROM THE JEPSON MANUAL |
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Jepson Interchange (more information) |
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©Copyright 1993 by the Regents of the University of California
Print edition is available from the University of California Press |
| The second edition of The Jepson Manual (2012) is available from the University of California Press | |
| See also the Jepson eFlora, which parallels the Second Edition |
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.
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.
| Introduced |
Tree < 20 m
Stem pendent ± to ground; twigs gray- to yellow-brown, long-soft-wavy-hairy, becoming glabrous, brittle at base
Leaves: stipules leaf-like; petiole generally with glands; young leaves glabrous or sparsely silky; mature blade 70–140 mm, linear-lanceolate, acuminate (base wedge-shaped), generally finely sharp-serrate, silky, becoming glabrous, lower surface glaucous
Inflorescence appearing with leaves, 18–35 mm, on leafy shoots 4–10 mm (staminate ± sessile); flower bract tawny
Staminate flower: stamens 2
Pistillate flower: ovary glabrous, stigma shrub-like, style ± 0.2 mm, stalk 0–0.3 mm
Chromosomes: 2n=76
Ecology: Disturbed places, around settlements
Elevation: generally < 1000 m.
Bioregional distribution: California
Distribution outside California: to se US; native to Asia
Mostly cultivated as ornamental, but many CVS and hybrids ± naturalized, including hybrids with S. alba L.
| YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps). |
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