[Mountain Ashes: The Genus Sorbus in the Columbia River Gorge of Oregon and Washington]

Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain Ash, Sitka Mountain-ash

Sorbus sitchensis var. grayi

Synonyms: Pyrus occidentalis, Sorbus occidentalis, Sorbus sitchensis ssp. grayi

Berries of Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain Ash, Sitka Mountain-ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Sorbus occidentalis, Sorbus sitchensis ssp. grayi)


Characteristics:

Sitka mountain ash is an attractive shrub or small tree with several stems from 2-5 meters high. Younger stems and winter buds are heavily haired and have reddish-purple bark. The older bark is grayish-red. The leaves are pinnately compound with 7-11 oval or oblong leaflets with the tips rounded or blunt. The thick leaflets have a dark green color above and are paler green beneath with rufous hairs along the midvein. The leaflets range from 2-5 cm long and are usually 1/3-2/5 as wide. The margins are coarsely serrate, usually near the tip, but occasionally 3/4 of the way to the base of the leaflet.

The inflorescence is a dense corymb of 15-80 flowers. Individual flowers have 5 white petals. The petals are rhombic to oval in shape and 4-5 mm long. The fruit are ellipsoid or subglobose in shape, red with a bluish cast, and up to 1 cm long.


Habitat:

Sitka mountain ash is found in subalpine and alpine habitats, either in open forests or open slopes, or in old burns or clear cuts.


Range:

Sitka mountain ash may be found from Alaska and the Yukon south through the Cascade and Olympic Mountains of Washington, and in the Cascades of Oregon to northern California. It is found eastward in the mountains to eastern British Columbia, northern Idaho, and northwestern Montana.

In the Columbia River Gorge, it may be found between the elevations of 2800'-4800' from Silver Star Mt. in the west to about Augspurger Mt. and Mt. Defiance in the east.


Flower of Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain Ash, Sitka Mountain-ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Sorbus occidentalis, Sorbus sitchensis ssp. grayi)

The photo above shows a close-up of one flower of Sitka mounain ash as seen near 3000' on the southern slopes of Mt. Adams..........July 11, 2005.

Upper leaf of Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain Ash, Sitka Mountain-ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Sorbus occidentalis, Sorbus sitchensis ssp. grayi) -- Lower leaf of Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain Ash, Sitka Mountain-ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Sorbus occidentalis, Sorbus sitchensis ssp. grayi)

The photos above show the upper (left) and lower (right) surfaces of the leaflets of Sitka mountain ash as taken on trail #95 in the Goat Rocks Wilderness..........August 30, 1998.

Paul Slichter