Oemleria cerasiformis, a shrub commonly known as osoberry, Squaw plum, or Indian plum, is the sole extant species in genus Oemleria. The species is native to the Pacific coast and coast ranges of North America, from British Columbia, Canada to Santa Barbara County, California, U.S.A., it is among the first plants to leaf out and flowers early in the spring. It reaches a height of 1.5–5 m and has lance-shaped leaves 5–12 cm long. The fruits of osoberry are edible and resemble small plums which are dark blue when ripe. Indigenous peoples of the Americas include osoberry in their diets, make tea of the bark, and chew its twigs to use as a mild anesthetic and aphrodisiac. One other fossil species is known from the genus, Oemleria janhartfordae from the Eocene Klondike Mountain Formation.

Description

Osoberry is a deciduous shrub that can reach an age of 50 years and grow to be 7 meters tall. The branches are spread out and occur in a variety of sizes. The bark is a smooth dark gray to reddish brown color, with twigs with similar coloring of green to reddish brown. The light green leaves of osoberry are simple, alternating, and oblong, with a length of 2-5 inches. These leaves are known to smell similar to cucumbers. Osoberry grows racemes of small white flowers that have 5 separate pistils, which can develop into a drupe. The bright orange lenticels grow up to a ½ inch in length. The racemes typically grow five to nine flowers, growing from the base of young shoots, and from short shoots of mature twigs. The flowers begin to grow as leaves are emerging and are fully bloomed before leaves have completely emerged. The amount of fruit yield varies depending on the amount of light in the spring. The plum fruit of osoberry begin as reddish pink and deepen to a deep blue color as they ripen. The fruit is known to be bitter, but sweetens as it ripens, tasting similar to cherries or watermelon. The mass of a mature fruit is around 200 grams. These plums are appealing to birds and are dispersed by avians. Osoberry is dioecious, with almost all plants being male or female. The shrubs have groups of up to twenty closely spaced stems of the same sex. The plants consist of almost completely strictly one gender, and the individuals are usually male. The reproductive biomass that males are mostly made up of are flowers and petals. On the other hand, the reproductive biomass of female individuals is largely made up of the fruit set. Only female osoberry produce fruit.

Habitat

Osoberry are found in the Pacific Northwest, ranging from Northern California to Southwestern British Columbia. The shrubs grow in places such as second-growth forests, stream terraces, forest, or roadside margins. Rosaceous flower fossils found in Northeastern Washington state show that Oemleria was present in the early Eocene of western North America.

Uses

The wood is exceptionally strong and fine grained. With stems generally less than two inches [5 cm] in diameter, this small size limits the size of products that can be made from it. The fairly common straight shoots make fine primitive arrows and the rare, large enough and straight stem can be fashioned into an excellent self bow. It is also suitable for small wooden tools such as spoons, combs, knitting needles, etc. The fine grain and lack of significant figure also make the wood well suited for fine detail carving. The Pacific coast tribes utilized its fruit, twigs, and bark, as food sources and for teas and medicine. It is one of the first tree-borne fruits to ripen in summer and as such was prized by indigenous peoples and wildlife alike. Fruiting is highly variable, with sunny locations producing more, as well as larger and sweeter fruits. The fruits can be eaten raw, or cooked when bitter; they tend to be somewhat astringent. Several Indigenous tribes from Western Washington, such as the Snohomish, Chehalis, and Squaxin tribes, ate the berries fresh. The Cowlitz tribe also ate the berries fresh, along with drying them for winter uses.

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