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 America. It produces a rosette of lobed or toothed leaves each up to 36 centimeters long around a woody caudex. It is normally night-blooming.
Eremothera boothii is a species of wildflower known as Booth's evening primrose. This plant is native to the western United States and northwestern Mexico where it is most abundant in arid areas such as deserts. This is an annual plant with hairy reddish-green stems and mottled foliage. The stem ends in a nodding inflorescence of many small flowers which may be white to red or yellowish, often with darker shades on the external surfaces of the four spoon-shaped petals. They have long stamens with clublike yellowish anthers. Flowers of this species tend to open at dusk rather than dawn as in many other Camissonia. The fruit is a twisted capsule one to 3 centimeters long. Plant appearances may vary across subspecies.
Gayophytum diffusum is a species of flowering plant in the evening primrose family known by the common name spreading groundsmoke. It is native to western North America where it is a common member of many different habitats. This is a spindly, branching annual herb reaching a maximum height of about half a meter. Its thin stems have sparse narrow leaves a few centimeters long. The occasional flowers are petite and usually white in color. The fruit is a cylindrical, knobby capsule up to 1.5 centimeters long.
Camissonia contorta is a species of evening primrose known by the common name plains evening primrose. It is native to western North America from British Columbia to California to Idaho, where it grows in many habitat types. It is an annual herb producing a slender, bending to curling red or green stem which is sometimes hairy. It is up to 30 centimeters long and erect or spreading out. The blue-green leaves are linear to very narrowly oval in shape and up to 3.5 centimeters long. The nodding inflorescence produces one or more small flowers. Each has bright yellow petals up to half a centimeter long, sometimes with small red dots near the bases. The fruit is a capsule about 3 centimeters long containing shiny seeds.
Tetrapteron palmeri is a species of evening primrose known by the common name Palmer evening primrose. It is native to the western United States from California to Idaho, where it grows in several habitat types, including desert and sagebrush. It is a roughly hairy annual herb growing in a low patch on the ground, generally with no stem. The leaves are widely lance-shaped and up to about 5 centimeters long, with a few small teeth along the edges. The nodding inflorescence produces flowers with yellow petals only 2 or 3 millimeters long each and a noticeable bulbous stigma tip which may be up to a centimeter wide. The fruit is a leathery capsule around half a centimeter long with small wings near the tip.
Chylismiella pterosperma is a species of evening primrose known by the common name wingfruit suncup and is the only species in the monotypic genus Chylismiella. It is native to the western United States, where it grows in several habitat types, including sagebrush. It is a slender annual herb producing an erect stem up to about 14 centimeters in height. The leaves are up to 3 centimeters long and densely coated in bristly hairs. The nodding inflorescence produces flowers with white petals each less than 3 millimeters long. They are sometimes yellow near the bases and fade to a purple color as they wither. The fruit is a straight capsule about 1 to 3 centimeters long with a thick wing down the middle.
Camissonia pubens is a species of evening primrose known by the common name hairy suncup. It is native to the desert and steppe of western Nevada and eastern California. It is an annual herb covered in glandular hairs generally made up of one or more erect, slender stems up to a third of a meter tall. The leaves are up to about 4 centimeters long and are lance-shaped with wavy, toothed edges. The nodding inflorescence produces flowers with yellow petals each a few millimeters long and sometimes dotted with red near the bases. The fruit is a straight or coiling capsule up to 5 centimeters long.
Camissonia pusilla is a species of evening primrose known by the common name little wiry suncup. It is native to the western United States from California to Idaho, where it grows in sagebrush and other habitat. It is a petite, hairy, glandular annual herb producing very slender erect stems up to about 22 centimeters in maximum height. The leaves linear with toothed edges and 1 to 3 centimeters long. The nodding inflorescence produces flowers with yellow petals 2 or 3 millimeters long and usually spotted with red near the bases. The fruit is a straight or coiling capsule up to 3 centimeters long.
Taraxia subacaulis is a species of evening primrose known by the common name diffuseflower evening primrose. It is native to the western United States, where it grows in several habitat types, especially in mountainous areas. It is a fleshy perennial herb growing from a taproot and usually lacking a stem. The leaves are lance-shaped to oval and up to 22 centimeters long and are borne on long petioles. The flower has yellow petals, each up to 1.5 centimeters long, and a large, bulbous stigma tip. The fruit is a leathery capsule 1 to 3 centimeters long.
Clarkia heterandra is a species of flowering plant in the evening primrose family known by the common name mountain clarkia. It is endemic to California, where it is from the forests and woodlands of several of eastern and western mountain ranges. It is an annual herb producing an erect, glandular stem to around half a meter in maximum height. The lance-shaped to oval leaves are up to 8 centimeters long and are borne on petioles of up to 2 centimeters. The top of the stem is occupied by the inflorescence, with open flowers and closed buds. The sepals remain fused as the flower blooms from one side. The pink petals are oval in shape and just a few millimeters long. There are 8 stamens, some large and some small and sterile. The fruit is a small, hard body 2 or 3 millimeters long containing 1 or 2 seeds.
Taraxia tanacetifolia is a species of evening primrose known by the common name tansyleaf evening primrose. It is native to the western United States, particularly the Great Basin and the mountains of the Pacific Northwest. It is a perennial herb growing from a woody taproot and spreading via lateral shoots. It lacks a stem and takes the form of a flat rosette of hairy leaves with a central inflorescence. The frilly leaves are long and narrow, lined with deep, irregular, narrow lobes. The leaf blades are up to about 30 centimeters long and are borne on long petioles. The flowers at the center of the rosette have bright yellow petals up to about 2.3 centimeters long. The fruit is a swollen, leathery capsule containing two rows of seeds.
Epilobium clavatum is a species of flowering plant in the evening primrose family known by the common names talus willowherb and clavatefruit willowherb. It is native to western North America from Alaska to northern California to Colorado, where it grows in rocky high mountain habitat such as talus. It is a clumping perennial herb forming bristly mounds up to about 20 centimeters high and spreading outward via tough stolons. The oval-shaped leaves are 1 to 3 centimeters long. The inflorescence is an erect raceme of flowers, each with four small pink petals. The fruit is a capsule up to 4 centimeters long.
Epilobium foliosum is a species of flowering plant in the evening primrose family known by the common names leafy willowherb and California willowherb. It is native to parts of western North America from British Columbia through California to Arizona, where it grows in many types of habitat, including disturbed areas.
Epilobium halleanum is a species of flowering plant in the evening primrose family known by the common name glandular willowherb. It is native to parts of western North America from British Columbia to New Mexico, where it grows in many types of habitat. It is an erect perennial herb growing up to about half a meter tall. The leaves are oval in shape low on the stem and narrower and somewhat lance-shaped higher, the longest about 4.5 centimeters long. The inflorescence is a raceme of glandular flowers, each with four notched white to pink petals a few millimeters long. The fruit is an elongated capsule up to 6 centimeters long.
Epilobium oregonense is a species of flowering plant in the evening primrose family known by the common name Oregon willowherb. It is native to western North America from British Columbia to Arizona, where it generally grows in moist places in several types of habitat. It is a perennial herb growing spindly erect stems approaching 40 centimeters high or sometimes forming mats spreading via stolons. The small leaves are rounded near the base of the plant and linear in shape farther up the stem. The inflorescence bears flowers with four white to pink petals each a few millimeters long. The fruit is an elongated capsule up to 5 centimeters in length which is borne on a long pedicel which may be longer than the capsule itself.
Epilobium pallidum is a species of flowering plant in the evening primrose family known by the common name largeflower spike-primrose. It is native to western United States, where it grows in moist areas in northern California, Oregon, and Idaho. It is an annual herb producing a narrow, upright stem up to 60 centimeters long lined with narrow oval leaves each up to 5 centimeters in length. The inflorescence atop the stem bears several flowers and hairy, leaflike bracts. Each flower has four bilobed petals each up to about a centimeter long and bright pink in color. The fruit is a beaked capsule between 1 and 2 centimeters long containing a row of tiny seeds.
Epilobium torreyi is a species of flowering plant in the evening primrose family known by the common names Torrey's willowherb and brook spike-primrose. It is native to western North America from British Columbia to California, where it grows in many types of habitat, often in moist areas. It is a hairy annual herb producing a narrow, upright stem often exceeding half a meter tall lined with narrow lance-shaped leaves. The hairy, glandular inflorescence bears tiny white or pink flowers. They are usually cleistogamous, remaining closed and self-pollinating. The fruit is a capsule up to about a centimeter long.
Oenothera californica, known by the common name California evening primrose, is a species of flowering plant in the evening primrose family.
Oenothera glazioviana is a species of flowering plant in the evening primrose family known by the common names large-flowered evening-primrose and redsepal evening primrose.
Oenothera xylocarpa is a species of flowering plant in the evening primrose family known by the common name woodyfruit evening primrose. It is native to the Sierra Nevada of California, its range extending just into western Nevada. It grows in coniferous forest and meadow habitat, often in soils rich in pumice and other gravel. It is a perennial herb growing from a thick taproot and producing a flat, dense rosette of hairy, gray-green leaves. There is no stem. The showy flowers appear amidst the leaves. Each has four petals which may be nearly 4 centimeters long, bright yellow in color, fading pink to red with age. The fruit is a straight, curving, or twisting capsule which may be up to 9 centimeters long.
