[Mountain Ash: The Genus Sorbus East of the Cascade Mountains of Oregon and Washington]

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

Sorbus sitchensis var. grayi

Synonyms: Pyrus occidentalis, Pyrus sambucifolia var. pumila, Sorbus occidentalis, Sorbus pumilus, Sorbus sambucifolia var. pumila, Sorbus sitchensis ssp. grayi

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

Dorsal leaf surface of Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain-ash, Sitka Mountain Ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Pyrus sambucifolia var. pumila, Sorbus occidentalis, Sorbus pumilus, Sorbus sambucifolia var. pumila, Sorbus sitchensis ssp. grayi)The photo at right illustrates the upper leaf surface of Sorbus sitchensis, taken on trail #95 in the Goat Rocks Wilderness ..........August 30, 1998. Note that the leaflets are only toothed above the midpoint, a characteristic of this variety.
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.


Varieties of Sitka Mt. Ash:

var. grayi -

var. sitchensis -


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.


Ventral eaf surface of  Dwarf Mountain Ash, Gray's Mountain Ash, Sitka Mountain-ash, Sitka Mountain Ash: Sorbus sitchensis var. grayi (Synonyms: Pyrus occidentalis, Pyrus sambucifolia var. pumila, Sorbus occidentalis, Sorbus pumilus, Sorbus sambucifolia var. pumila, Sorbus sitchensis ssp. grayi)

The photo above illustrates the underside of a leaf of Sorbus sitchensis, taken on trail #95 in the Goat Rocks Wilderness........August 30, 1998. Note that the leaflets are only toothed above the midpoint, a characteristic of this variety.

Paul Slichter