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.
NATIVE Habit: Shrub. Stem: trunks < 9 m. Leaf: blade thick, base rounded to subcordate, tip rounded to acute, margin generally +- flat, adaxially dark green, dull, midrib, major veins generally indented, abaxially yellow-green. Ecology: Wet places; Elevation: 1200--2400 m. Bioregional Distribution: KR, NCoRH, CaRH, SNH; Distribution Outside California: to Alaska, western Canada, Wyoming, New Mexico. Flowering Time: Apr--Jun Note: 2 other subspecies in Alaska, Canada, Europe. Synonyms: Alnus tenuifolia Nutt. Jepson eFlora Author: John O. Sawyer, Jr. Index of California Plant Names (ICPN; linked via the Jepson Online Interchange) Previous taxon: Alnus cordata Next taxon: Alnus rhombifolia
Citation for this treatment: John O. Sawyer, Jr. 2012, Alnus incana subsp. tenuifolia, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=49084, accessed on February 06, 2025.
Citation for the whole project: Jepson Flora Project (eds.) 2025, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on February 06, 2025.
MAP CONTROLS 1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
(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 occurrence).
MAP LEGEND View all CCH records 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.
READ ABOUT YELLOW FLAGS
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 (fruiting time in some monocot genera).