Jepson eFlora: Taxon page
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Salix alba
WHITE WILLOW

Higher Taxonomy
Family: SalicaceaeView DescriptionDichotomous Key

Common Name: WILLOW FAMILY
Habit: 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.
Genera In Family: 58 genera, 1210 species: widespread in tropics, northern temperate, arctic. Note: 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.
eFlora Treatment Author: John O. Sawyer, Jr., except as noted
Scientific Editor: Thomas J. Rosatti.
Genus: SalixView DescriptionDichotomous Key

Common Name: WILLOW
Habit: Shrub, tree; dioecious; bud scale 1, not sticky, margins generally fused (or free, overlapping). Stem: twigs generally flexible, generally not glaucous. Leaf: generally alternate; stipules generally vestigial on first leaves, leaf-like on later; mature blade linear to broadly obovate, entire to toothed, generally +- hairy; petiole glands generally 0. Inflorescence: catkin, blooming before, with, or after leaves, sessile or terminating +- short leafy or bracted shoot ("on leafy shoot" or "on bracted shoot," "catkin length" including leafless or bractless part of subtending shoot); 1 flower bract subtending each flower, deciduous or persistent, brown, black, or 2-colored (paler proximally, darker distally; darker generally +- brown). Flower: perianth reduced to adaxial nectary (rarely also with abaxial nectary, then free or fused into shallow cup). Staminate Flower: stamens (1)2(10); nectary generally 1. Pistillate Flower: ovary stalked or sessile, style generally 1, stigmas 2, each 2-lobed, deciduous or persistent; nectary generally 1, generally rod-like. Fruit: valves 2.
Species In Genus: +- 450 species: +- worldwide, especially northern temperate, arctic. Etymology: (Latin: ancient name) Note: Difficult, highly variable, many hybrids. Not all specimens key easily; sprouts, other extreme forms not included in keys, may require field comparisons. Studies of chromosome numbers, hybridization needed. Inclusion of Salix sessilifolia Nutt. in TJM (1993) based on misidentification of plants belonging to Salix melanopsis. Fruit length as given throughout excludes the stalk (stipe). Hair lengths: minute, < +- 0.5 mm; short, +- 0.5 mm; long, > +- 0.5 mm. Salix commutata Bebb, treated as misapplied to Salix eastwoodiae in TJM (1993), may occur in northern California mountains; Salix bonplandiana expected in s-most California. For alternate treatments, see Dorn (e.g., 2000 Brittonia 52:1--19).
eFlora Treatment Author: George W. Argus

Salix alba L.
NATURALIZED
Habit: Tree < 25 m. Stem: erect to spreading; twigs +- yellow or gray to red-brown, flexible or +- brittle at base, silky, glabrous in age. Leaf: later stipules leaf-like; petiole 3--13 mm, with glands; young leaves densely silky; mature blade 63--115 mm, lanceolate to narrowly oblong, acuminate (base wedge-shaped or acute), finely serrate, abaxial hairs generally densely long-silky, straight, to +- 0. Inflorescence: blooming with leaves, pistillate 31--51 mm, on leafy shoots 3--14 mm; flower bract +- tan, sparsely hairy, tip rounded; pistillate bracts deciduous. Staminate Flower: stamens 2; nectaries adaxial, abaxial. Pistillate Flower: ovary glabrous, stalk 0.2--0.8 mm, style 0.16--0.44 mm. Chromosomes: 2n=76.
Ecology: Disturbed places, generally near settlements; Elevation: probably < 20 m. Bioregional Distribution: CA; Distribution Outside California: to eastern North America; native to Europe. Flowering Time: May--Jun Note: Mostly cultivated as ornamental, but many cultivars, hybrids +- naturalized.
Unabridged Note: Hybrid formerly known as Salix ×rubens Schrank (Salix alba × Salix fragilis) now correctly recognized as Salix ×fragilis L. (Salix alba × Salix euxina I.V. Belyaeva), probably only cultivated in California.
eFlora Treatment Author: George W. Argus
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Citation for this treatment: George W. Argus 2016. Salix alba, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=42673, accessed on May 06, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 06, 2016.


Geographic subdivisions for Salix alba:
CA;
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.
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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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Data provided by the participants of the Consortium of California Herbaria.
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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.