''Oenothera'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of about 145 species of herbaceous flowering plants

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

to the Americas. It is the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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 Primula ''Primula'' () is a genus of herbaceous flowering plants in the family Primulaceae. They include the primrose ('' P. vulgaris''), a familiar wildflower of banks and verges. Other common species are '' P. auricula'' (auricula), '' P. veris'' (cow ...

'').

Description

The species vary in size from small alpine plants 10 centimeters tall, such as ''O. acaulis'' from

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, to vigorous lowland species growing to 3 meters, such as ''O. stubbei'' from

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. The leaves form a basal rosette at ground level and spiral up to the flowering stems. The blades are dentate or deeply lobed (

pinnatifid Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and i ...

). The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s of many species open in the evening, hence the name "evening primrose". They may open in under a minute. Most species have yellow flowers, but some have white, purple, pink, or red. Most native desert species are white. ''

Oenothera caespitosa ''Oenothera caespitosa'', known commonly as tufted evening primrose, desert evening primrose, rock-rose evening primrose, or fragrant evening primrose, is a perennial plant of the genus ''Oenothera'' native to much of western and central North A ...

'', a species of western North America, produces white flowers that turn pink with age. One of the most distinctive features of the flower is the stigma, which has four branches in an X shape.

Ecology

Plant Oenothera biennis evening primrose 11 on black L Plymouth Mass USA D 210714

''Oenothera'' flowers are

pollinated by insects Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Flowers pollinated by insects typically advertise themselves with bright colours, some ...

, such as

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s and bees. Like many other members of the Onagraceae, however, the pollen grains are loosely held together by

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