The Genus Sorbus

California Mountain Ash: Sorbus californica -

Cascade Mountain-ash: Sorbus scopulina var. cascadensis (Synonym: Sorbus cascadensis) - Shrub to 12 feet high, with flat-topped clusters of 5 petaled white flowers. Leaves duller green, pinnately compound with 7 to 13 leaflets, the leaflet margins serrate less than 3/4 the length. Fruits red.

Rocky Mountain Mountain Ash: Sorbus scopulina var. scopulina - Leaves green, pinnately compound with 13 leaflets.

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) - Shrub to 12 feet high, with flat-topped clusters of 5-petaled white flowers. Leaves shiny, pinnately compound with 9-13 leaflets, the leaflets serrate above mid-leaflet to the tip. Berries orangish red.

Sitka Mountain Ash, Sitka Mountain-ash: Sorbus sitchensis var. sitchensis - Shrub to 12 feet high, with flat-topped clusters of 5-petaled white flowers. Leaves shiny, pinnately compound with 9-13 leaflets, the leaflets serrate almost the full length. Berries orangish red.