Ephedra is agenus ofgymnospermshrubs. As of July 2025[update], 74 species, and two hybrids, are accepted.[3] The species ofEphedra 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.[3] It is the only extant genus in its family,Ephedraceae, and order, Ephedrales, and one of the three extant genera of the divisionGnetophyta together withGnetum andWelwitschia.
The familyEphedraceae, of whichEphedra is the only extant genus, aregymnosperms, and generally shrubs, sometimes clambering vines, and rarely, small trees. Members of the genus frequently spread by the use ofrhizomes.[4]
The stems are green and photosynthetic.[5] 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.[4] Most species have rudimentary leaves without chlorophyll or photosynthesis, but a few, likeE. altissima, develop normal, slender leaf-like leaves up to 5 cm (2.0 in) long and 0.5–1 mm (0.020–0.039 in) also as adults.[6]
The plants are mostlydioecious, with the pollenstrobili in whorls of 1–10, each consisting of a series ofdecussate[7]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 inE. frustillata) or red. There are generally 1–2 yellow to dark brown seeds per strobilus.[4]
The oldest known members of the genus are from theEarly Cretaceous around 125 million years ago, with records being known from theAptian-Albian of Argentina,[10] China,[11] Portugal and the United States.[12] The fossil record ofEphedra outside of pollen disappears after the Early Cretaceous.[13]Molecular clock estimates have suggested that last common ancestor of livingEphedra species lived much more recently, during theEarly Oligocene around 30 million years ago.[14] However, pollen modified from the ancestral condition of the genus with branched pseudosulci (grooves), whichevolved in parallel in the living North American and Asian lineages is known from theLate Cretaceous, suggesting that the last common ancestor is at least this old.[13]
Ephedraceae are adapted to extremely arid regions, growing often in high sunny habitats, and occur as high as 4,000 m (13,000 ft) above sea level in both theAndes and theHimalayas.[4] They make up a significant part of the North AmericanGreat Basin sage brush ecosystem.
Today,Ephedra plants are found no further south than 3°N in theSaharo-Arabian region. However, researchers have discovered evidence of this drought-resistant plant living over 1,000 km (620 mi) further south atOldupai Gorge around one million years ago, based on fossil pollen, preserved tap roots, and supporting indicators of arid conditions.[17]
Remains of a buriedNeanderthal found atShanidar cave in Iraqi Kurdistan, over 50,000 years old was found associated withEphedra 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.[18]
In addition, archaeological remains ofEphedra dating back 15,000 years have been discovered atTaforalt Cave in Morocco. Fossil cones ofEphedra were found concentrated in the cemetery area, specifically within a human burial.[19]
In the United States, ephedra supplements were banned from the market in the early twenty-first century due to serious safety risks.[21] Plants of the genusEphedra, includingE. sinica and others, were used intraditional medicine for treating headache andrespiratory infections, but there is little to no publicly available evidence that they are effective or safe for these purposes.[21]
Ephedra has also had a role as a precursor in the clandestine manufacture ofmethamphetamine.[22]
Alkaloids obtained from the species ofEphedra used in herbal medicines, such aspseudoephedrine and ephedrine, can cause cardiovascular events.[20] These events have been associated with arrhythmias, palpitations, tachycardia and myocardial infarction.[20]Caffeine consumption in combination with ephedrine has been reported to increase the risk of these cardiovascular events.[20][21]
For a review of thealkaloid distribution in different species of thegenusEphedra see Jian-fang Cui (1991).[24] Other American and European species ofEphedra, e.g.E. nevadensis (Nevada Mormon tea) have not been systematically assayed; based on unpublished field investigations, they contain very low levels (less than 0.1%) or none at all.[25]
^Kim HK, Choi YH, Erkelens C, Lefeber AW, Verpoorte R (January 2005). "Metabolic fingerprinting of Ephedra species using 1H-NMR spectroscopy and principal component analysis".Chemical & Pharmaceutical Bulletin.53 (1):105–9.doi:10.1002/pca.2800020305.PMID15635242.
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