Oemleria cerasiformis Temporal range: Eocene - recent[1] PreꞒ Ꞓ O S D C P T J K Pg N
Conservation status
Least Concern  (IUCN 3.1)[2]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Rosales
Family:	Rosaceae
Subfamily:	Amygdaloideae
Tribe:	Exochordeae
Genus:	Oemleria
Species:	O. cerasiformis
Binomial name
Oemleria cerasiformis (Torr. & Gray ex Hook. & Arn.) J.W.Landon
Synonyms[3][4][5]
Oemleria synonymy Nuttallia cerasiformis Torr. & A. Gray ex Hook. & Arn. Osmaronia cerasiformis (Torr. & A. Gray ex Hook. & Arn.) Greene

Oemleria cerasiformis, a shrub commonly known as osoberry,^[6] squaw plum,^[7] Indian plum,^[8] or Indian Peach,^[9] is the sole extant species in genus Oemleria.^[10] The deciduous and perennial osoberry is one of the first plants to have its flowers bloom and leaves bud in the late winter.^[9] The shrub can grow up to 7 meters tall, with spread out branches^[11] that grow small white flowers and bitter fruit that sweeten when ripened.^[12] Osoberry is dioecious, with females producing fruit, and males producing a high reproductive biomass of pollen and flowers.^[13] Animals and insects aid in internal animal dispersion of seeds and pollination.^[9]

The species is native to the Pacific coast and coast ranges of North America, from British Columbia, Canada, to Santa Barbara County, California, United States.^[8] Fossil records give evidence of this range being true in the Eocene epoch as well.^[10] The favored habitat conditions for the shrub include sunlight, moist soil, and low elevation.^[9]

Native Americans of the West coast tribes had several uses for osoberry, serving purposes such as medicine, food, and tools.^[14]

David Douglas and John Scouler were the first botanists to collect Oemleria in 1825, followed by Tolmie, Gairdner, and Nuttall, The genus was first named Nuttallia in 1838, but that name had already been given to three other genera. ^[15] In 1841, Reichenbach published Oemleria as a nomen novum, in honor of Augustus Gottlieb Oemler, a naturalist in Dresden who had lived in Georgia, had known Nuttall, and had given Reichenbach specimens of plants from America.^[16] Reichenbach did not publish a name for the species under the new genus, and most^[specify] botanists later adopted Osmaronia cerasiformis, published by Edward Lee Greene in 1891, until 1975, when J.W. Landon reasserted the prioity of Reichenbach’s name and published the full proper name of the species.^[17][18]

Osoberry is a deciduous^[11] and perennial^[9] shrub that can reach an age of 50 years and grow to be 7 meters (23 ft) tall. The branches are spread out and occur in a variety of sizes.^[11] The bark is a smooth dark gray to reddish-brown color, with twigs with similar coloring of green to reddish brown.^[19] The bright orange lenticels (pores),^[9] grow up to 0.5 inches (1.3 cm) in length on twigs of osoberry.^[19] The light green leaves of osoberry are simple, alternating, and oblong, with a length of 2–5 inches (5.1–13 cm).^[19] These leaves are known to smell similar to cucumbers.^[12]

Osoberry grows racemes of small white flowers that have 5 separate pistils, which can develop into a drupe.^[13] A drupe can have 10–20 flowers growing from it.^[9] 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.^[11] The amount of fruit yield varies depending on the amount of light in the spring,^[13] with sunny locations producing more, as well as larger and sweeter fruits.^[20] 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.^[12] The mass of a mature fruit is around 200 grams.^[11] The osoberry fruit contains a pit, which cyanoglucosides (also found in almonds) can be found in.^[9]

Osoberry are pollinated by native pollinators such as bees, moths, butterflies, hummingbirds, and more. The nectar in the flowers of osoberry is an important source of food for these pollinators in the early spring.^[9]

Osoberry seeds are dispersed through internal animal dispersal. Many animals eat osoberries, primarily birds, along with small mammals, coyotes, foxes, deer, and bear.^[9] The seeds are dispersed through the feces of these animals, germinating where they are defecated.^[21]

Osoberry is dioecious, with almost all plants being male or female.^[13] 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.^[11] The reproductive biomass that males are mostly made up of are flowers and petals.^[13] On the other hand, the reproductive biomass of female individuals is largely made up of the fruit set.^[22] Only female osoberry produce fruit.^[13]

Osoberry flowers bloom and leaves bud in the late winter to early spring. Osoberry are relatively short compared to trees in the Pacific Northwest. The early bud timing allows the osoberry to get access to sunlight that is not as easily available in later months. When taller trees or shrubs have grown their leaves, this can block sunlight from reaching an osoberry shrub.^[9]

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,^[13] forest,^[11] or roadside margins.^[12] Osoberry grow in places with sunlight, and usually below elevations of 1,000 feet (300 m). The shrub can grow up to 5,000 feet (1,500 m) in elevation. Moist soil is preferred, but not grounds that are saturated in winter months.^[9]

Oemleria cerasiformis is the only extant member of its genus, Oemleria. A fossil species is known from the genus, Oemleria janhartfordae from the Eocene Klondike Mountain Formation. Rosaceous flower fossils found in Northeastern Washington state show that Oemleria was present in the early Eocene of western North America.^[10]

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.^[20]

The wood is exceptionally strong and fine-grained. But, 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.^[20]

Native Americans made use of the shrub's bark, using it to bind harpoon tips. Native tribes also used the bark of osoberry for treating tuberculosis.^[9] The bark was also used as a mild laxative,^[9] and chewing its twigs had mild anesthetic and aphrodisiac effects.^[14]

Currently, osoberry is popular for restoration projects in the Pacific Northwest. Living osoberry branches can be used as live stakes in restoration projects to prevent erosion. The roots of osoberry are fibrous and are good for preventing erosion of soil.^[9]

The osoberry fruits can be eaten raw or cooked when bitter; they tend to be somewhat astringent.^[20] The Indigenous peoples of the Americas included osoberry in their diets, making tea of the bark.^[14] 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.^[7]

• 
  Fruits of O. cerasiformis
• 
  O. cerasiformis as its leaves begin to yellow in mid-summer, Pierce County, Washington

• Media related to Oemleria cerasiformis at Wikimedia Commons
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