Jepson Flora Project: Jepson Interchange    

link to manual TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

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



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.



John O. Sawyer, Jr.

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)


P. balsamifera L. subsp. trichocarpa (Torr. & A. Gray) Brayshaw


Stem: crown wide; trunk < 30 m; twigs brown, becoming gray; winter buds finely ciliate, very resinous, fragrant when opening
Leaf: petiole 1/3–1/2 blade length, lower side round, upper channeled, with pair of glands at junction with blade; blade 3–7 cm, narrowly to widely ovate, base round to cordate, tip acute to tapered, margin finely scalloped, upper surface green, lower glaucous, often stained with brown resin
Chromosomes: 2n=38
Ecology: Scattered. Alluvial bottomlands, streamsides
Elevation: < 2800 m.
Bioregional distribution: California Floristic Province, Great Basin Floristic Province
Distribution outside California: to Alaska, n Rocky Mtns, Utah, n Baja California
Flowering time: Feb–Apr
Synonyms: P. t. Torr. & A. Gray
Reference: [Brayshaw 1965 Canad Field-Naturalist 79:91–95]
Horticultural information: IRR or WET, SUN: 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; susceptible to galls.

previous taxon | next taxon
bioregional map for POPULUS%20balsamifera%20subsp.%20trichocarpa being generated

Retrieve Jepson Interchange Index to Plant Names entry for Populus balsamifera subsp. trichocarpa
Retrieve dichotomous key for Populus
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
Return to the Jepson Interchange main page
Return to treatment index page

University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites
Copyright © by the Regents of the University of California