The Genus Crataegus
1. Castlegar Hawthorn: Crataegus castlegarensis -
2. Columbia Hawthorn, Piper's Hawthorn: Crataegus chrysocarpa var. piperi (formerly Crataegus columbiana var. piperi) - Large shrub or small tree to 18 feet. Branches have numerous stout thorns from 40-70 mm in length. White flowers are small, less than dime size, but clustered in groups of 5 to 30. The flowers have 5 petals each. The leaves are simple, and variable in shape, some lobed and others with toothed edges only at the tip of the leaf. Stamens number 10 or fewer.
3. Black Hawthorn, Douglas' Hawthorn: Crataegus douglasii (old variety douglasii) - Big, coarse shrub or small tree up to 12 meters high with rough, scaly, brown bark. Young branches dark red-brown. Thorns 12-25 mm long. Leaves 25-75 mm long, broadly obovate, double-toothed above the base. The leaf blades may be more or less lobed. Flowers usually many in flat-topped corymbs. Flowers about 15 mm wide with short triangular sepals. Petals white and orbicular in shape. Stamens number 10 with pink anthers.
4. Western Large-thorned Hawthorn: Crataegus macracantha var. occidentalis (formerly Crataegus columbiana var. occidentalis -
5. Oneseed Hawthorn, Common Hawthorn: Crataegus monogyna - Introduced species. A rare escapee east of the Cascades?
6. Suksdorf's Hawthorn: Crataegus suksdorfii (formerly Crataegus douglasii var. suksdorfii) - Big, coarse shrub or small tree up to 12 meters high with rough, scaly brown bark. Thorns 12-25 mm long. The leaves are generally with toothed or double-toothed margins and blades widest at mid-leaf, tapering gradually to a point. Flowers usually many in flat-topped corymbs. Petals white and orbicular in shape. Stamens number 20.