mountain alder (thinleaf alder)
Betulaceae (Birch family)
Introduction to Vascular Plants
Photograph
Map
Distribution of Alnus incana subsp. tenuifolia
Click here to view the full interactive map and legend
Species Information
General:
Deciduous shrub or tree, up to 12 m tall, usually 2-5 m tall, new growth short-hairy; axillary buds with short stalks; bark scaly, often lichen-covered, yellowish-brown or grey.
Leaves:
Alternate, deciduous, smooth, coarsely to irregularly toothed, the teeth pointing outwards, leaf margins not rolled under, brownish in the fall.
Flowers:
Inflorescence of male and female catkins, which open before the leaves on previous year's growth; male catkins with stalks.
Fruits:
Small nutlets, without wings; female cones 1-1.5 cm long, egg-shaped.
Illustration
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
USDA Species Characteristics
Flower Colour:
Purple
Blooming Period:
Early Spring
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
Source: The USDA
Ecology
The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)
| Site Information |
Value / Class |
||
|
Avg |
Min |
Max |
|
| Elevation
(metres) |
1046 | 393 | 1693 |
| Slope
Gradient (%) |
10 | 0 | 80 |
|
Aspect (degrees) |
45 | 0 | 360 |
| Soil
Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric] |
5 | 1 | 7 |
| Modal
Nutrient Regime
Class |
D | ||
| #
of field plots species was recorded in: |
161 | ||
| Modal
BEC Zone Class |
SBS | ||
|
All BEC Zones (# of stations/zone) species was recorded in |
BG(1), BWBS(6), ESSF(16), ICH(38), IDF(22), MS(27), PP(1), SBS(50) | ||
|
Source:
Klinkenberg 2013
|
|||
Habitat and Range
Moist forests, streamsides, bogs and fens in the montane zone; common in BC east of the Coast-Cascade Mountains; N to AK, YT and NT, E to SK, and S to NM, AZ and CA.Status Information
Synonyms
Synonyms and Alternate Names:
Alnus purpusii Callier
Alnus purpusii Callier
Alnus incana var. occidentalis subsp. rugosa (Dippel) C.L. Hitchc.
Alnus incana var. occidentalis (Dippel) C.L. Hitchc.
Alnus incana var. virescens S. Wats.
Alnus tenuifolia Nutt.
Alnus tenuifolia var. occidentalis (Nutt.) Breit.
Taxonomic Keys
KEY TO ALNUS
1. Leaves finely once or twice saw-toothed; axillary buds unstalked, pointed; male catkins unstalked; stalks as long as or longer than the conelike sillicles..........................A. viridis 1. Leaves coarsely to irregularly round-toothed; axillary buds pedunculate, blunt or short-pointed; male catkins stalked; stalks shorter than the conelike silicles 2. Leaf margins rolled under; nutlets with narrow-winged margins.......................................A. rubra 2. Leaf margins not rolled under; nutlets wingless..................................A. incana SOURCE: Illustrated Flora of British Columbia, Volume 2 |