Ephedra is a genus of gymnosperm shrubs — and occasionally small trees or scrambling vines — that stands as the sole living representative of the family Ephedraceae and the order Ephedrales. Together with Gnetum and Welwitschia, it is one of just three extant genera in the ancient gymnosperm division Gnetophyta, a lineage whose relationships to the conifers and to the flowering plants have long puzzled botanists. As of July 2025, roughly 74 species and 2 hybrids are recognized worldwide, although species concepts have shifted considerably since the last comprehensive monograph by O. Stapf in 1889.
The plants are immediately recognizable for what they lack as much as for what they have. Leaves are reduced to small scales, borne opposite one another or in whorls of three at swollen nodes along the stems, and they are often shed early. Photosynthesis is carried out instead by the slender, jointed, yellowish- to olive-green twigs, which give the genus its common English names of joint-fir and jointed-stem fir. Twig diameter, the degree to which branches are smooth or scabrous, and the precise arrangement of the scale leaves are all useful field characters for distinguishing species.
Ephedra is dioecious: pollen cones and seed cones are produced on separate male and female plants, and both are arranged in whorls at the nodes. Female cones may be biovulate or uniovulate, with varying degrees of bract fusion, and they range in outline from lanceoloid to globose. At maturity, the small seeds — typically one or two per cone — are often partially enclosed by fleshy bracts that turn white, yellow, or bright red, lending some species a berry-like appearance even though no true fruit is formed. The base chromosome number is x = 7.
The genus has an almost cosmopolitan distribution across the world's drylands, missing only from Australia. Species occur from southwestern North America (Arizona, California, Nevada, New Mexico, Colorado, Oregon, Texas and adjacent states) southward through the Andes of western South America, throughout the Mediterranean basin and North Africa, across the Arabian Peninsula and the Iranian plateau, and through Central Asia into the high steppes and deserts of Tibet, Mongolia, northern China and southern Siberia. Wherever they grow, Ephedra plants are characteristic of arid and semi-arid habitats, where the reduced leaves and photosynthetic green stems function as classic xerophytic adaptations to drought and intense sunlight.
Ephedra is also one of the most economically and historically significant gymnosperms. The aerial parts of several species contain the alkaloids ephedrine and pseudoephedrine, sympathomimetic compounds that have been used medicinally for thousands of years and isolated commercially in the modern era. This chemistry — combined with its long deep history of human use — sets the genus apart from almost any other group of "primitive" seed plants still alive today.
Distribution
Ephedra is one of the most widespread gymnosperm genera, recorded from more than a hundred regions across the world's drylands and absent only from Australia. In North America the genus is concentrated in the southwestern United States — Arizona, California, Nevada, New Mexico, Colorado, Oregon, Oklahoma and Texas — with major centers of diversity on the Colorado Plateau and in the Sonoran Desert. In western South America it ranges through Ecuador, Peru, Bolivia, Chile (from the north to the south of the country) and across much of Argentina, with outliers into southern Brazil. Across the Old World it occupies the Mediterranean basin (Spain, Portugal, France, Italy, Greece, the Balkans, Turkey and the major Mediterranean islands of Corsica, Sardinia, Sicily, the Balearics, Crete, the Canary Islands and Madeira) and extends through North Africa from Morocco to Egypt and south into the Sahel as far as Chad, Mali, Mauritania, Sudan and the Horn of Africa. From the Arabian Peninsula and the Levant it stretches across Iran, Afghanistan, Pakistan, India and Nepal into Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan), Tibet, Qinghai, Inner Mongolia, Manchuria and southern Siberia, including Tuva, Buryatia and the Primorye region. Within Europe, Switzerland has a single native representative — Ephedra helvetica.
Ecology
Ephedra is overwhelmingly a plant of arid and semi-arid landscapes, with its global distribution concentrated in Mediterranean climates, Central Asian steppe and desert zones, and the dry interiors of the New World. Its morphology reads as a textbook case of xerophytic adaptation: leaves are reduced to scales and shed early, while the photosynthetic role is taken over by jointed, waxy, yellowish to olive-green stems that minimize transpiration in dry, sunny environments. The genus tolerates rocky and sandy substrates and is often a conspicuous component of open shrublands and rocky slopes.
History
Ephedra has one of the longest documented histories of human use of any gymnosperm. Pollen of the genus has been found in Neanderthal-era archaeological contexts, and roughly 15,000-year-old fossil cones are known from Morocco. In China the plant — called mahuang (麻黃) — has reportedly been used medicinally for around seven thousand years, traditionally to treat headaches and respiratory complaints, though modern clinical evidence for many of these applications remains limited. The genus was formally described by Linnaeus in 1753, building on Tournefort's earlier usage. In the twentieth century, ephedrine isolated from Ephedra distachya and related species became a widely used decongestant and bronchodilator, but concerns about cardiovascular harm — arrhythmias, palpitations, tachycardia and myocardial infarction, especially in combination with caffeine — led the United States to ban dietary supplements containing ephedra in the early 21st century.
Cultural Uses
Several species of Ephedra contain the alkaloids ephedrine and pseudoephedrine, typically at concentrations of 1–4% of dry weight and occasionally as high as 6%. These sympathomimetic compounds have decongestant, bronchodilator and stimulant effects, and they underlie the genus's long history of medicinal and ceremonial use, particularly in East Asia where Ephedra sinica is the principal commercial source of ma huang. The same chemistry is responsible for the genus's modern reputation as a hazardous over-the-counter supplement: ephedrine and pseudoephedrine can trigger arrhythmias, palpitations, tachycardia and myocardial infarction, with the risk substantially increased by combination with caffeine. In North America, several native species are traditionally brewed as a stimulant tea — the basis of common names such as "Mormon tea."
Taxonomy Notes
Ephedra was published by Carl Linnaeus in Species Plantarum in 1753 (page 1040), with the authority cited as Ephedra Tourn. ex L. in recognition of Tournefort's earlier usage. It is the only living genus in the family Ephedraceae and the order Ephedrales, and one of three extant genera in the gymnosperm division Gnetophyta, alongside Gnetum and Welwitschia. Roughly 74 species and 2 hybrids are accepted today, though no comprehensive modern monograph has been produced since O. Stapf's treatment of 1889, and North American species alone are recognized as falling into at least three distinct groups within the genus. The base chromosome number is x = 7. Diagnostic characters used to separate species include female cone structure (whether biovulate or uniovulate, and the degree of bract fusion), twig diameter (which ranges from about 0.4 to 3.5 mm), leaf arrangement (opposite versus whorled in threes), and seed morphology.
