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 December 09, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on December 09, 2016.


Betula occidentalis
click for enlargement
© 2016 Julie Kierstead Nelson
Betula occidentalis
click for enlargement
© 2016 Julie Kierstead Nelson
Betula occidentalis
click for enlargement
© 2016 Julie Kierstead Nelson
Betula occidentalis
click for enlargement
© 2016 Julie Kierstead Nelson
Betula occidentalis
click for enlargement
© 2016 Julie Kierstead Nelson
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. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
READ ABOUT YELLOW FLAGS
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.