''Oenothera deltoides'' subsp. ''howellii'', the Antioch Dunes evening primrose, is an

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

subspecies of plant in the family

Onagraceae The Onagraceae are a family of flowering plants known as the willowherb family or evening primrose family. They include about 650 species of herbs, shrubs, and trees Oenothera ''Oenothera'' is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to ...

'', and species '' Oenothera deltoides''.

Description

''Oenothera deltoides'' subsp. ''howellii'' is a short-lived

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

plant with thick stems varying from 4 to 40 inches in length. It is multi-branching in form and tends to grow in large tufts. The grayish colored leaves are shaped like a

lance A lance is a spear designed to be used by a mounted warrior or cavalry soldier (lancer). In ancient and medieval warfare, it evolved into the leading weapon in cavalry charges, and was unsuited for throwing or for repeated thrusting, unlike s ...

and are about 1 to 5 inches long with many hairs, primarily short with only a few being longer. Its flowers are white with inch-long petals and yellow

stamens The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

. It blooms from March to September. The subspecies is often confused with ''Oenothera deltoides'' ssp. ''cognata'' that grows in an area southeast of the protected area. The Antioch Dunes Evening Primrose blooms for only one night. The flowers are a major host plant for a rare species of sweat bee, '' Sphecodogastra antiochensis''.

Distribution and habitat

''Oenothera deltoides'' subsp. ''howellii'' is a

plant that grows only in an environmentally sensitive sand dune habitat located near the meeting of the

Sacramento River The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento� ...

and the

San Joaquin River The San Joaquin River (; es, Río San Joaquín) is the longest river of Central California. The long river starts in the high Sierra Nevada, and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suis ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. In 1979 ''Oenothera deltoides'' subsp. ''howellii'', the Antioch Dunes Evening Primrose, was declared an endangered species. Currently, its habitat is restricted to the

Antioch Dunes National Wildlife Refuge Antioch Dunes National Wildlife Refuge is a sensitive sand dune habitat located near the city of Antioch, California on the south shore of the San Joaquin River-Stockton Deepwater Shipping Channel. It serves as a refuge for three endangered sp ...

, the last remnant of an isolated nine kilometer stretch of sand dune habitat. The refuge was formed in 1980 to prevent extinction of this plant, as well as Lange's metalmark butterfly (''

Apodemia mormo langei ''Apodemia mormo langei'', the Lange's metalmark butterfly, is an endangered North American butterfly. It is a subspecies of the Mormon metalmark and belongs to the family Riodinidae. The butterfly is endemic to California, where it is known fr ...

'') and the Contra Costa wallflower ('' Erysimum capitatum'' var. ''angustatum''). This refuge is the first national wildlife refuge in the U.S. formed to protect endangered plants and insects, and it is open for viewing to the public only under supervision because of the sensitive status of these species.

Endangered status

In 2007 a five-year review of its endangered status was completed, and its status was continued unchanged.

References

External links

* * {{Taxonbar, from=Q7078659 deltoides subsp. howellii Endemic flora of California Natural history of the Central Valley (California) Night-blooming plants Plant subspecies Antioch, California Natural history of Contra Costa County, California Endemic flora of the San Francisco Bay Area