Jepson eFlora: Taxon page
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Betula occidentalis
WATER BIRCH

Higher Taxonomy
Family: BetulaceaeView DescriptionDichotomous Key

Common Name: BIRCH FAMILY
Habit: Shrub, tree; monoecious. Stem: trunk < 35 m; bark smooth to scaly, peeling in thin layers or not, lenticels present or not. Leaf: simple, alternate, petioled, deciduous; stipules deciduous; blade ovate to elliptic, generally serrate, generally +- doubly so. Inflorescence: catkin, generally appearing before leaves, often clustered; bracts each subtending 2--3 flowers, 3--6 bractlets. Staminate Inflorescence: pendent, +- elongate. Pistillate Inflorescence: pendent or erect, developing variously in fruit (see key to genera). Staminate Flower: sepals 0--4, minute; petals 0; stamens 1--10; pistil vestigial or 0. Pistillate Flower: sepals 0--4; petals 0; stamens 0; pistil 1, ovary inferior or superior, chambers 2, each 1-ovuled by abortion, stigmas 2. Fruit: achene, nut, winged or not, subtended or enclosed by 1--2 bracts.
Genera In Family: 6 genera, 155 species: generally northern hemisphere; some cultivated.
eFlora Treatment Author: John O. Sawyer, Jr.
Scientific Editor: Thomas J. Rosatti.
Genus: BetulaView DescriptionDichotomous Key

Common Name: BIRCH
Stem: trunk < 30 m; bark smooth or scaly, aromatic, often peeling in thin layers; twigs puberulent, glandular, or both; lenticels prominent; winter buds sessile, 3-scaled. Leaf: glandular-hairy; blade 2--5 cm, wide-elliptic, base +- truncate to tapered. Staminate Inflorescence: 2--7 cm; bracts each subtending 3 flowers, 3 bractlets. Pistillate Inflorescence: 2--3 cm; bracts each subtending 3 flowers, 3 bractlets. Staminate Flower: sepals 4; stamens 2. Pistillate Flower: sepals 0. Fruit: many, in a non-cone-like catkin, not enclosed by bract, winged; bracts lobed, papery, released with but not attached to fruit.
Species In Genus: 50 species: circumboreal. Etymology: (Latin: birch) Note: Important wildlife food; wood used for interior finishing; many species cultivated.

Betula occidentalis Hook.
NATIVE
Stem: trunks to 10 m; bark red-brown to black, not peeling; twigs with large resin glands, hairy. Leaf: petiole < 15 mm, hairy; blade 2--5 cm, wide-ovate, glands especially adaxially, base +- truncate to tapered. Pistillate Inflorescence: 3--5 cm; bract fringed with hairs.
Ecology: Streamsides, springs; Elevation: 600--2900 m. Bioregional Distribution: KR, CaRH, SNH, GB, DMtns; Distribution Outside California: scattered in western North America. Flowering Time: Apr--May
eFlora Treatment Author: John O. Sawyer, Jr.
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Previous taxon: Betula glandulosa
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botanical illustration including Betula occidentalis

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Citation for this treatment: John O. Sawyer, Jr. 2016. Betula occidentalis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=15658, accessed on May 01, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 01, 2016.


Betula occidentalis
click for enlargement
© 2008 Steve Matson
Betula occidentalis
click for enlargement
© 2008 Steve Matson
Betula occidentalis
click for enlargement
© 2008 Steve Matson

More photos of Betula occidentalis in CalPhotos


Geographic subdivisions for Betula occidentalis:
KR, CaRH, SNH, GB, DMtns;
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).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

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