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John O. Sawyer, Jr., except as noted

Shrub, tree; dioecious (monoecious). Stem: trunk < 40 m; wood soft; bark smooth, bitter; buds scaly. Leaf: simple, alternate, deciduous; stipules generally present, deciduous or not, often large. Inflorescence: catkin [or various, or flowers 1]; each flower subtended by 1 bract. Flower: perianth modified into non-nectariferous, cup- or saucer-shaped structure or reduced to adaxial nectary (rarely also with abaxial nectary, then free or fused into shallow cup). Staminate flower: stamens 2–many. Pistillate flower: pistil 1, ovary superior to 1/2-inferior, chambers generally 2–4, placentas parietal, stigma lobes 2–4. Fruit: berry, drupe, or 2–4-valved capsule. Seed: often with basal tuft of hairs.
58 genera, 1210 species: widespread in tropics, northern temperate, arctic. Now including many genera (e.g., Flacourtia, Idesia, Xylosma) formerly in Flacourtiaceae, at least in part because of presence on leaf margins in both families of salicoid teeth (vein extending to tooth tip). In California (and generally outside California), Populus pollinated by wind, Salix by insects, wind. Hybrids common; identification often difficult. —Scientific Editor: Thomas J. Rosatti.

Key to Salicaceae

Tree. Stem: < 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. Leaf: juvenile, adult, late-season leaves may differ in size, shape, hairiness; generally glabrous; blade 3–11 cm, elliptic to deltate, veins pinnate or ± palmate, tip generally elongate. Inflorescence: catkin pendent, 3–8 cm; bract cut into narrow segments; flowers sessile; nectary a cup- or saucer-like disk. Flower: perianth modified into non-nectariferous, cup- or saucer-shaped structure. 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.
40 species: northern hemisphere. (Latin: name for plants of this genus) [Hamzeh et al. 2006 J Torrey Bot Soc 133:519–527]
Unabridged references: [Hamzeh & Dayanandan 2004 Amer J Bot 91:1398–1408]

Key to Populus

Tree < 20 m; crown wide or slender. Stem: twigs yellow-brown, winter buds red-brown. Leaf: petiole 1/3–2/3 blade; blade 3–5 cm, deltate to rhomboid, glabrous, adaxially green, base ± truncate to tapered, tip acute, margin crenate to serrate.
Disturbed places near settlements; 600–1800 m. San Francisco Bay Area, South Coast, East of Sierra Nevada, Mojave Desert, expected elsewhere; native to Europe. Feb–May [Online Interchange]
Unabridged synonyms: [Populus nigra var. italica Du Roi]
Unabridged references: [Eckenwalder 1982 Madroño 29:67–78]
Unabridged note: Plants with slender crowns are called Lombardy Poplar, but they all have been propagated from a single clone and therefore are not worthy of formal taxonomic recognition, so that the scientific name that has been applied to them (Populus nigra L. var. italica Du Roi) is to be treated as a synonym, as is Populus nigra L. var. nigra, which refers to plants with wide crowns that are called Black Poplar. Also reported for California are Populus ×inopina (Populus nigra × Populus fremontii), Populus ×canadensis (Populus nigra × Populus deltoides).

Previous taxon: Populus fremontii subsp. fremontii
Next taxon: Populus tremuloides


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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 25 2015
Citation for this treatment: [Author of taxon treatment] 2013. Populus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 25 2015

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Geographic subdivisions indicated for the distribution of Populus nigra Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.