Jepson eFlora: Taxon page
Vascular Plants of California
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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
Jepson eFlora Author: John O. Sawyer, Jr.
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Previous taxon: Alnus incana subsp. tenuifolia
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Botanical illustration including Alnus rhombifolia

botanical illustration including Alnus rhombifolia

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Citation for this treatment: John O. Sawyer, Jr. 2012, Alnus rhombifolia, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=12722, accessed on September 17, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora, http://ucjeps.berkeley.edu/eflora/, accessed on September 17, 2019.

Alnus rhombifolia
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© 2006 Steve Matson
Alnus rhombifolia
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© 2017 Julie Kierstead Nelson
Alnus rhombifolia
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© 2013 Julie Kierstead Nelson
Alnus rhombifolia
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© 2009 George W. Hartwell
Alnus rhombifolia
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© 2009 Neal Kramer
Alnus rhombifolia
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© 2008 Keir Morse

More photos of Alnus rhombifolia in CalPhotos



Geographic subdivisions for Alnus rhombifolia:
CA-FP, MP (uncommon), w DSon
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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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All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.