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
For up-to-date information about California vascular plants, visit 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. fremontii S. Watson subsp. fremontii


Stem: crown wide; trunk < 20 m; twigs yellow, becoming gray, glabrous to hairy; winter buds resinous
Leaf: petiole 1/2 to = blade length, laterally compressed near blade; blade 3–7 cm, deltate, base slightly cordate to flat, tip ± tapered, margin coarsely scalloped, surfaces yellow-green, glabrous to hairy, often stained with milky resin
Ecology: Scattered. Alluvial bottomlands, streamsides
Elevation: < 2000 m.
Bioregional distribution: California (except Modoc Plateau)
Distribution outside California: to c Rocky Mtns, n Mexico
Flowering time: Mar–Apr
Synonyms: var. arizonica (Sarg.) Jeps.; var. macdougalii (Rose) Jeps
[Eckenwalder J Arnold Arbor 58:193–208]
Horticultural information: IRR or WET, SUN: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; susceptible to mistletoe; INV; STBL.

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bioregional map for POPULUS%20fremontii%20subsp.%20fremontii being generated
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).

Retrieve Jepson Interchange Index to Plant Names entry for Populus fremontii subsp. fremontii
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
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