[Alders East of the Cascade Mountains of Oregon and Washington]

Gray Alder, Mountain Alder, Thinleaf Alder, Thin-leaf Alder

Alnus incana ssp. tenuifolia

Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia

Dorsal leaf surface of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Ventral leaf surface of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Close-up views of the upper leaf surface (left) and lower leaf surface (right) of mountain alder as seen from seeps along the Canyon Mountain Trail #218, Strawberry Mountain Wilderness.........August 19, 2011.

Leaf of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Leaf bud of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Close-up views of the upper leaf surface and a leaf bud of mountain alder as seen from the shoreline of the Deschutes River in the eastern Columbia River Gorge..........September 29, 2007.

Close-up of the ventral leaf surface of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Ventral leaf surface of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Close-up views of the lower leaf surface of mountain alder as seen from the shoreline of the Deschutes River in the eastern Columbia River Gorge..........September 29, 2007.

Leaves and maturing cones of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia)

Mountain alder leaves as seen at the crossing of Whychus Creek along the Alder Springs Trail #855, Crooked River National Grasslands.......May 11, 2018.

Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Leaves and stem of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Mountain alder growing in a sedge meadow along Summit Creek where it crosses Forest Service Road 1647, Malheur National Forest.........August 4, 2011.

Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia) - Leaf underside of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia)

Mountain alder growing along the Line Butte Trail #807 on the southern slopes of Lookout Mountain, Ochoco National Forest..........June 22, 2017.

Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia)

Ventral leaf surface of mountain alder as seen at Potter Meadows across Forest Road 38 from the southern trailhead for the Ochoco Mountain Trail, Ochoco National Forest.........July 13, 2017.

Leaves of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Lower leaf surface of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) - Leaves and catkins of Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia)

Additional photos of mountain alder growing along Forest Service Road #16 at Big Creek in Logan Valley, Malheur National Forest.........August 20, 2011.

Gray Alder, Mountain Alder, Thinleaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus incana var. virescens, Alnus x purpusii, Alnus tenuifolia)

Mountain alder observed along Indian Creek at the northwest corner of Big Summit Prairie, Ochoco National Forest.......May 27, 2018.

Paul Slichter