Jepson eFlora: Taxon page
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Alnus rhombifolia
WHITE ALDER

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: AlnusView DescriptionDichotomous Key

Common Name: ALDER
Stem: trunk < 35 m; bark smooth, gray to brown; twigs glabrous to fine-hairy, red-gray; lenticels small; winter buds stalked, 0--6-scaled. Leaf: glabrous to fine-hairy; blade 3--15 cm, cordate to elliptic or diamond-shaped. Staminate Inflorescence: 5--20 cm; bracts each subtending 3 flowers, 4 bractlets. Pistillate Inflorescence: 5--20 mm; bracts each subtending 2 flowers, 4 fused bractlets. Staminate Flower: sepals 4; stamens 1--4. Pistillate Flower: sepals 0. Fruit: many, in cone-like catkin, not enclosed by bract, winged, bracts 3 mm, woody, persistent.
Species In Genus: +- 25 species: northern hemisphere, South America. Etymology: (Latin: alder) Note: Root nodules contain nitrogen-fixing bacteria; wood used for interior finishing, to smoke fish, meats.

Alnus rhombifolia Nutt.
NATIVE
Habit: Tree. Stem: trunk < 35 m. Leaf: blade thick, base rounded to tapered, tip rounded to acute, margin generally +- flat, adaxially green, midrib, major veins not indented, abaxially yellow-green.
Ecology: Along permanent streams; Elevation: 100--2400 m. Bioregional Distribution: CA-FP, MP (uncommon), w DSon; Distribution Outside California: to Washington, Idaho. Flowering Time: Jan--Apr
eFlora Treatment Author: John O. Sawyer, Jr.
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Previous taxon: Alnus incana subsp. tenuifolia
Next taxon: Alnus rubra

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Citation for this treatment: John O. Sawyer, Jr. 2016. Alnus rhombifolia, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=12722, accessed on May 25, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 25, 2016.


Alnus rhombifolia
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© 2008 Keir Morse
Alnus rhombifolia
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© 2013 Julie Kierstead Nelson
Alnus rhombifolia
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© 2006 Steve Matson
Alnus rhombifolia
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© 2006 Steve Matson
Alnus rhombifolia
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© 2008 Keir Morse
Alnus rhombifolia
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© 2009 Neal Kramer

More photos of Alnus rhombifolia in CalPhotos


Geographic subdivisions for Alnus rhombifolia:
CA-FP, MP (uncommon), w DSon;
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.
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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.