Ephedra is a genus of gymnosperm shrubs. , 74 species, and two hybrids, are accepted. The species of Ephedra are widespread in many arid regions of the world, ranging across southwestern North America, southern Europe, northern Africa, southwest and central Asia, northern China, and western South America. It is the only extant genus in its family, Ephedraceae, and order, Ephedrales, and one of the three extant genera of the division Gnetophyta together with Gnetum and Welwitschia.

In temperate climates, most Ephedra species grow on shores or in sandy soils with direct sun exposure. Common names in English include joint-pine, jointfir, Mormon-tea, or Brigham tea. The Chinese name for Ephedra species is mahuang (). Ephedra is the origin of the name of the stimulant ephedrine, which the plants contain in significant concentration.

Description The family Ephedraceae, of which Ephedra is the only extant genus, are gymnosperms, and generally shrubs, sometimes clambering vines, and rarely, small trees. Members of the genus frequently spread by the use of rhizomes.

The stems are green and photosynthetic. The leaves are opposite or whorled. The typical scalelike leaves are fused into a sheath at the base and is often shed soon after development. There are no resin canals. Most species have rudimentary leaves without chlorophyll or photosynthesis, but a few, like E. altissima, develop normal, slender leaf-like leaves up to long and also as adults.

The plants are mostly dioecious, with the pollen strobili in whorls of 1–10, each consisting of a series of decussate bracts. The pollen is furrowed. The female strobili also occur in whorls, with bracts which fuse around a single ovule. Fleshy bracts are white (such as in E. frustillata) or red. There are generally 1–2 yellow to dark brown seeds per strobilus.

Taxonomy The genus Ephedra was first described in 1753 by Carl Linnaeus. The type species is E. distachya . The family, Ephedraceae, was first described in 1829 by Barthélemy Charles Joseph Dumortier.

Evolutionary history The oldest known members of the genus are from the Early Cretaceous around 125 million years ago, with records being known from the Aptian-Albian of Argentina, China, Portugal and the United States. The fossil record of Ephedra outside of pollen disappears after the Early Cretaceous. Molecular clock estimates have suggested that last common ancestor of living Ephedra species lived much more recently, during the Early Oligocene around 30 million years ago. However, pollen modified from the ancestral condition of the genus with branched pseudosulci (grooves), which evolved in parallel in the living North American and Asian lineages is known from the Late Cretaceous, suggesting that the last common ancestor is at least this old.

Species

, Plants of the World Online accepts the following 74 species, and two hybrids: Ephedra alata Decne. – North Africa, Arabian Peninsula Ephedra altissima Desf. non-Bové (1834), non-Delile (1813), non-Buch (1828) – high-climbing jointfir – North Africa, Canary Islands Ephedra americana Humb. & Bonpl. ex Willd. – Bolivia, Ecuador, Peru, Argentina, Chile Ephedra antisyphilitica Berland ex C.A.Mey. – clapweed, erect ephedra – Texas, Oklahoma, New Mexico, Nuevo León, Coahuila, Chihuahua Ephedra aphylla Forssk. – eastern Mediterranean from Libya and Cyprus to the Persian Gulf Ephedra × arenicola H.C.Cutler – Arizona, Utah (hybrid, E. cutleri × E. torreyana) Ephedra aspera Engelm. ex S.Watson – boundary ephedra, pitamoreal – Texas, New Mexico, Arizona, Utah, Nevada, California, Chihuahua, Durango, Zacatecas, Sinaloa, Sonora, Baja California Ephedra aurantiaca Takht. & Pachom. – Caucasus, Kazakhstan, Turkmenistan Ephedra aurea Brullo et al. Ephedra boelckei F.A.Roig – Argentina Ephedra botschantzevii Pachom. – Kazakhstan, Tuva region of Siberia Ephedra breana Phil. – frutilla de campo – Peru, Bolivia, Chile, Argentina Ephedra brevifoliata Ghahr. – Iran Ephedra californica S.Watson – California ephedra, California jointfir – California, western Arizona, Baja California Ephedra chengiae Yang & Ferguson Ephedra chilensis C.Presl – pingo-pingo - Chile, Argentina Ephedra ciliata Fisch. & C.A.Mey. (syn. Ephedra foliata Boiss. ex C.A.Mey.) – North Africa, Middle East, India Ephedra compacta Rose – widespread in much of Mexico Ephedra coryi E.L.Reed – Cory's ephedra – Texas, New Mexico Ephedra cutleri Peebles – Navajo ephedra, Cutler's ephedra, Cutler Mormon-tea, Cutler's jointfir – Colorado, Utah, Arizona, New Mexico, Wyoming Ephedra dahurica Turcz. – Siberia, Mongolia Ephedra dawuensis Y.Yang – Sichuan Ephedra distachya L. – joint-pine, jointfir – southern Europe and central Asia from Portugal to Kazakhstan Ephedra × eleutherolepis V.A.Nikitin – Tajikistan (hybrid E. intermedia × E. strobilacea) Ephedra equisetina Bunge – ma huang – Caucasus, Central Asia, Siberia, Mongolia, Gansu, Hebei, Inner Mongolia, Ningxia, Qinghai, Shanxi, Xinjiang Ephedra fasciculata A.Nelson – Arizona ephedra, Arizona jointfir, desert Mormon-tea – Arizona, California, Nevada, Utah Ephedra fedtschenkoae Paulsen – Central Asia, Siberia, Mongolia, Xinjiang Ephedra foeminea Forssk. – North Africa, Somalia, Balkans, Italy, Middle East; naturalized in Santa Barbara County of California Ephedra fragilis Desf. – joint pine – Mediterranean, Canary Islands, Madeira Ephedra frustillata Miers – Patagonian ephedra – Chile, Argentina Ephedra funerea Coville & C.V.Morton – Death Valley ephedra, Death Valley jointfir – California, Arizona, Nevada Ephedra gerardiana Wall. ex Klotzsch & Garcke – Gerard's jointfir, shan ling ma huang – Himalayas, Tibet, Yunnan, Siberia, Central Asia Ephedra glauca Regel – Iran east to Mongolia and northern China Ephedra gracilis Phil. ex Stapf Ephedra holoptera Riedl – Iran Ephedra intermedia Schrenk & C.A.Mey. – zhong ma huang – China, Siberia, Central Asia, Himalayas, Iran, Pakistan Ephedra kardangensis P.Sharma & P.L.Uniyal – western Himalayas Ephedra karumanchiana S.K.Patel, S.M.Patil, Raole & K.S.Rajput – Northwest India Ephedra laristanica Assadi – Iran Ephedra likiangensis Florin – Guizhou, Sichuan, Tibet, Yunnan Ephedra lomatolepis Schrenk – Kazakhstan, Tuva region of Siberia Ephedra milleri Freitag & Maier-St. – Oman, Yemen Ephedra minuta Florin – Qinghai, Sichuan Ephedra monosperma J.G.Gmel. ex C.A.Mey. – dan zi ma huang – Siberia, Mongolia, much of China including Tibet and Xinjiang Ephedra multiflora Phil. ex Stapf – Chile, Argentina Ephedra nebrodensis Tineo - Mediterranean region except northeast Africa Ephedra nevadensis S.Watson – Nevada ephedra, Nevada jointfir, Nevada Mormon-tea – Baja California, California, Arizona, Nevada, Utah, Oregon Ephedra nutans Miau & Xiao L.Pan – Xinjiang Ephedra ochreata Miers – Argentina Ephedra oxyphylla Riedl – Afghanistan Ephedra pachyclada Boiss. – Middle East from Sinai and Yemen to Pakistan Ephedra pedunculata Engelm. ex S.Watson – vine ephedra, vine jointfir – Texas, Chihuahua, Coahuila, Durango, San Luis Potosí, Nuevo León, Zacatecas Ephedra pentandra Pachom. – Iran Ephedra procera Fisch. & C.A.Mey. − Iran, Caucasus Ephedra przewalskii Stapf – Central Asia, Mongolia, Pakistan, Gansu, Inner Mongolia, Ningxia, Qinghai, Tibet Ephedra pseudodistachya Pachom. – Siberia, Mongolia Ephedra regeliana Florin – xi zi ma huang – Central Asia, Siberia, Pakistan, Xinjiang Ephedra rhytidosperma Pachom., syn. E. lepidosperma C.Y.Cheng – Gansu, Inner Mongolia, Ningxia, Mongolia Ephedra rituensis Y.Yang, D.Z.Fu & G.H.Zhu – Qinghai, Xinjiang, Tibet Ephedra rupestris Benth. – Ecuador, Peru, Bolivia, Argentina Ephedra sarcocarpa Aitch. & Hemsl. – Pakistan, Afghanistan Ephedra saxatilis (Stapf) Royle ex Florin Ephedra sinica Stapf – cao ma huang, Chinese ephedra – Mongolia, Siberia, Primorye, Manchuria Ephedra somalensis Freitag & Maier-St. – Somalia, Eritrea Ephedra stipitata Biswas & Rita Singh Ephedra strobilacea Bunge – Iran, Central Asia Ephedra strongylensis Brullo et al. Ephedra tilhoana Maire – Chad Ephedra torreyana S.Watson – Torrey's ephedra, Torrey's jointfir, Torrey's Mormon-tea, cañutillo – Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Chihuahua Ephedra transitoria Riedl – Iraq, Syria, Palestine, Saudi Arabia Ephedra triandra Tul. − Bolivia, Argentina Ephedra trifurca Torrey ex S.Watson – longleaf ephedra, longleaf jointfir, longleaf Mormon-tea, popotilla, teposote – California, Arizona, New Mexico, Texas, Chihuahua, Sonora, Baja California Ephedra trifurcata Zöllner Ephedra tweedieana C.A.Mey. – Brazil, Argentina, Uruguay Ephedra viridis Coville – green ephedra, green Mormon-tea – California, Nevada, Utah, Arizona, New Mexico, Colorado, Wyoming, South Dakota, Oregon Ephedra vvedenskyi Pachom. – Iran, Caucasus, Turkmenistan

Distribution The genus is found in dry and desert regions worldwide, except for Australia.

Ecology

Ephedraceae are adapted to extremely arid regions, growing often in high sunny habitats, and occur as high as above sea level in both the Andes and the Himalayas. They make up a significant part of the North American Great Basin sage brush ecosystem.

Today, Ephedra plants are found no further south than 3°N in the Saharo-Arabian region. However, researchers have discovered evidence of this drought-resistant plant living over further south at Oldupai Gorge around one million years ago, based on fossil pollen, preserved tap roots, and supporting indicators of arid conditions.

Human use

Remains of a buried Neanderthal found at Shanidar cave in Iraqi Kurdistan, over 50,000 years old was found associated with Ephedra pollen among those of other plants. While some authors have suggested that these represent plant remains deliberately buried alongside the Neanderthal, other authors have suggested that natural agents like bees may have been responsible for the accumulation of pollen.

In addition, archaeological remains of Ephedra dating back 15,000 years have been discovered at Taforalt Cave in Morocco. Fossil cones of Ephedra were found concentrated in the cemetery area, specifically within a human burial. According to Zoroastrian belief, the species Ephedra procera is identified as haoma, and the plant and its extract are considered divine.

The Ephedra alkaloids, ephedrine and pseudoephedrine — constituents of E. sinica and other members of the genus — have sympathomimetic and decongestant qualities, and have been used as dietary supplements, mainly for weight loss. The drug ephedrine is used to prevent low blood pressure during spinal anesthesia.

In the United States, ephedra supplements were banned from the market in the early twenty-first century due to serious safety risks. Plants of the genus Ephedra, including E. sinica and others, were used in traditional medicine for treating headache and respiratory infections, but there is little to no publicly available evidence that they are effective or safe for these purposes.

Ephedra has also had a role as a precursor in the clandestine manufacture of methamphetamine.

Adverse effects Alkaloids obtained from the species of Ephedra used in herbal medicines, such as pseudoephedrine and ephedrine, can cause cardiovascular events. These events have been associated with arrhythmias, palpitations, tachycardia and myocardial infarction. Caffeine consumption in combination with ephedrine has been reported to increase the risk of these cardiovascular events.

Economic botany and alkaloid content