Euphorbia is a very large and diverse genus of flowering plants, commonly called spurge, in the spurge family (Euphorbiaceae). "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae, not just to members of the genus. Some euphorbias are commercially widely available, such as poinsettias at Christmas. Some are commonly cultivated as ornamentals, or collected and highly valued for the aesthetic appearance of their unique floral structures, such as the crown of thorns plant. Euphorbias from the deserts of Southern Africa and Madagascar have evolved physical characteristics and forms similar to cacti of North and South America, so they are often incorrectly referred to as cacti. Some are used as ornamentals in landscaping, because of beautiful or striking overall forms, and drought and heat tolerance.
Chamaesyce is a genus of plants in the family Euphorbiaceae. Recent phylogenetic studies have shown that Chamaesyce is deeply nested within the broader Euphorbia. Specifically, Chamaesyce is very closely related to plants like Euphorbia pulcherrima, the popular poinsettia. Currently, all species have now been reclassified as species of Euphorbia. Specifically, this group now belongs to Euphorbia subgenus Chamaesyce section Anisophyllum. Taxonomically speaking, Chamaesyce is considered a synonym of Euphorbia.
Euphorbia albomarginata, whitemargin sandmat or rattlesnake weed, is a small low-growing perennial, in the spurge family native to desert, chaparral, and grassland habitats of southwestern North America, from southern and central California to Northern Mexico and Louisiana.
Euphorbia misera is a semi-succulent shrub in the genus Euphorbia commonly known as the cliff spurge or coast spurge. A drought-deciduous shrub, it is typically found as a gnarled, straggly plant occupying seashore bluffs, hills and deserts. Like other members of its genus, it has a milky sap, which can be found exuding out of the light gray bark when damaged. The alternately-arranged leaves are round and folded in the middle, with small hairs on them. The "flowers" can be found blooming year-round, and are colored maroon or yellow in the center with 5 white to light-yellow petal-like appendages attached outside. This species is native to the Baja California peninsula and Sonora in Mexico, and the coast of southern California in the United States, where it is a rare species. It is threatened in some localities by the development of its coastal habitat, which tends to be prime locations for high-end residential and commercial developments.
Euphorbia polycarpa is a species of spurge known by the common name smallseed sandmat. It is native to the southwestern United States and northern Mexico, especially the deserts and other dry, sandy areas. This is a perennial herb producing stems that trail along the ground to form a clump or mat, sometimes growing somewhat upright. The leaves are each under a centimeter long. They are round or oval-shaped and have triangular stipules at the bases. What looks like a single flower is actually an inflorescence of many staminate (male) flowers united around a single central pistillate (female) flower. Bracts surrounding the flower unit are white and petal-like. The fruit is a thin spherical capsule less than 2 millimeters wide layered over a seed.
Euphorbia fendleri is a species of Euphorbia known by the common name Fendler's sandmat. It is native to much of the southwestern and central United States and northern Mexico, where it grows in scrub and woodland habitat in desert and plateau regions. This is a mat- or clump-forming reddish-green plant with a crooked, creeping, hairless stem. The leaves are rounded, oval, or spade-shaped, smooth along the edges and generally coming to a point, and not much more than one centimeter in maximum length. The tiny inflorescence is a cyathium with white-edged, scalloped appendages surrounding the actual flowers. There is a ring of 25 to 35 staminate flowers around one pistillate flower. The ovary of the pistillate flower enlarges into a lobed fruit about 2 millimeters long.
Euphorbia hooveri is a species of euphorb known by the common names Hoover's sandmat and Hoover's spurge. It is endemic to California, where it grows in the rare vernal pools of the Central Valley. Due to the elimination of most of its habitat, it became a federally listed threatened species in 1997.
Euphorbia micromera is a species of flowering plant in the family Euphorbiaceae. It is known by the common name Sonoran sandmat. It is native to the southwestern United States from California to Texas, and northern Mexico, where it grows in sandy soils in desert and other dry habitat. It is an annual herb forming a small mat of slender stems. The hairy to hairless leaves are oblong in shape and just a few millimeters long. The tiny inflorescence is a cyathium less than a millimeter wide. It lacks the appendages that many similar species have in their cyathia. It has only a central female flower and 2 to 5 male flowers surrounded by round red nectar glands. The fruit is a minute round capsule.
Euphorbia nutans is a species of Euphorbia known by the common names eyebane and nodding spurge. It is native to much of the United States, Eastern Canada, Mexico, Central America, the Caribbean, and Venezuela.
Euphorbia ocellata is a species of Euphorbia known by the common name Contura Creek sandmat. It is native to the southwestern United States where it grows in many types of habitats. This is a small annual herb with pairs of oblong to lance-shaped leaves, each leaf up to about 1.5 centimeters long. The inflorescence is a cyathium only 2 millimeters wide. It consists of petal-like appendages surrounding the actual flowers, each with a round nectar gland at its base. The appendages are sometimes absent. The flowers include one female flower ringed by up to 60 male flowers. The fruit is a lobed, spherical capsule less than 3 millimeters wide.
Euphorbia parishii, known by the common name Parish's sandmat, is a species of euphorb. It is native to the sandy soils of the deserts in California and Nevada. It is a perennial herb forming a small patch on the ground. The slender, hairless, tangling stems have pairs of tiny, pointed oval leaves, each leaf just a few millimeters long. The minute inflorescence is a cyathium one millimeter wide. It is made up of several rounded nectar glands in shades of yellow to deep red surrounding many tiny male flowers and one female flower. The latter develops into a spherical fruit two millimeters wide.
Euphorbia prostrata is a species of spurge known by the common name prostrate spurge or prostrate sandmat.
Euphorbia revoluta is a species of euphorb known by the common name threadstem sandmat. It is native to Mexico and the southwestern United States from California to the Rocky Mountains. It is an annual herb producing thin, erect stems with pairs of linear leaves, each leaf up to 2.6 centimeters long. The inflorescence is a cyathium with rounded nectar glands surrounding one female flower and several male flowers. There are sometimes white petal-like appendages as well. The Navajo used this plant as a skin lotion.
Euphorbia serpens is a species of Euphorbia known by the common name matted sandmat. It is native to South America but it can be found on most continents as an introduced species and often a weed. This is an annual herb forming a mat of prostrate stems which root at nodes where the stem comes in contact with the ground. The oval leaves occur in oppositely arranged pairs, each leaf less than a centimeter long. The inflorescence is a cyathium with scalloped white petal-like appendages surrounding the actual flowers. A red nectar gland is at the base of each appendage, and at the center of the cyathium are several male flowers around one female flower. The fruit is a lobed, spherical capsule.
Euphorbia serpyllifolia is a species of euphorb known by the common names thymeleaf sandmat or thyme-leafed spurge. It is native to a large part of North America from Canada to Mexico, where it is a common member of the flora in many types of habitat. This is an annual herb growing as a prostrate mat or taking a somewhat erect form. The oblong leaves are up to about 1.5 centimeters long, sometimes hairy and finely toothed along the edges. The tiny inflorescence is a cyathium about a millimeter wide. It bears scalloped white petal-like appendages arranged around the actual flowers. At the center are several male flowers and one female flower, which develops into a lobed, oval fruit up to 2 millimeters wide. This plant had a number of traditional medicinal uses for many Native American groups.
Euphorbia setiloba is a species of euphorb known by the common name Yuma sandmat. It is native to the southwestern United States and northern Mexico, where it grows in dry habitat. This is a small, clumping annual herb with slender stems lined with pairs of tiny hairy leaves. Each leaf is just a few millimeters long and oval in shape with a bluntly pointed tip. The minute inflorescence is a cyathium less than two millimeters wide. It has distinctive appendages which are white with a few narrow, sharp-pointed lobes. There is a red nectar gland at the base of each. At the center of the appendages are the actual flowers, one female and several male. The ovary of the female flower develops into a hairy, spherical fruit about a millimeter wide.
Euphorbia schizoloba is a species of euphorb known by the common name Mojave spurge. It is native to the southwestern United States, where it grows in desert hills and mountains. It is a perennial herb producing upright stems up to 40 centimeters tall, sometimes with coats of sparse hairs. The stems are lined with alternately arranged leaves which are oval with pointed tips and measure up to 2 centimeters in length. The inflorescence is a cyathium with bell-shaped bracts surrounding four tiny glands with flat, fringed appendages. At the center of this arrangement are several staminate flowers and one long pistillate flower.
Euphorbia eleanoriae is a rare species of flowering plant in the euphorb family known by the common name Nā Pali sandmat. It is endemic to Kauaʻi, Hawaii. Like other native Hawaiian euphorbs it is called ʻakoko locally. This plant was only discovered in 1992 and described to science in 1996 as Chamaesyce eleanoriae. At that time there were fewer than 500 plants known, all occurring in small populations scattered across the sheer cliffs along the Nā Pali Coast of Kauaʻi. By 2001 the total population had already dropped; only three populations were found, for a total of fewer than 50 plants. The plant was federally listed as an endangered species of the United States in 2010.
Euphorbia kuwaleana is a rare species of flowering plant in the euphorb family known by the common name kokomalei. It is endemic to Oahu, Hawaii, where it is known only from a four-kilometer stretch of the Waianae Range. Like other Hawaiian euphorbs, this plant is known locally as `akoko. It is a federally listed endangered species of the United States.
Euphorbia missurica, commonly called prairie sandmat, or Missouri spurge, is a species of flowering plant in the spurge family (Euphorbiaceae). It is native to North America, where it is found primarily in area of the Great Plains. Its natural habitat is in dry, often calcareous areas, including glades, bluffs, and open woodlands.
