Distribution of Ephedra (link to illustration at Caveney et. al. [2001]).

Ephedra

Linnaeus 1753

Common Names

Mormon-tea, joint-fir, cañatilla, popotillo, tepopote (Stevenson 1993), 麻黄属 ma huang shu [Chinese] (Fu et al. 1999).

Taxonomic notes

"The North American species of Ephedra are well defined based on combinations of vegetative and reproductive characters. Putative hybrids reported and described by Cutler (1939) appear to be products of singular events... Infraspecific taxa are not recognized in this treatment because there appear to be no consistent defining characters and no geographic correlations; previous recognition of infraspecific taxa (Cutler 1939) appears to be based on random variability" (Stevenson 1993).

The treatment of Ephedra here is still incomplete. Among the species that do not yet have pages are E. aphylla Forssk., E. botschantzevii Pachom., E. chilensis K. Presl, E. foemina Forssk, E. foliata Boiss. ex C.A. Mey., and E. tweediana Fisch. et C.A. Meyer.

Description

Shrubs or vines, dioecious (rarely monoecious), with erect, procumbent or climbing stems. Branches jointed, much branched, photosynthetic, yellowish green to olive-green when young. Branchlets opposite or whorled, green, terete, longitudinally grooved. Leaves opposite or in whorls of 3, scalelike, generally ephemeral, mostly not photosynthetic; resin canals absent. Cotyledons 2. Cones terminal or axillary, ovoid to elliptic. Pollen cones solitary or clustered at nodes, each composed of 2-8 descussate pairs or 3-part whorls of membranous bracts, proximal bracts empty; each distal bract subtending a male flower composed of 2 basally fused, orbicular or obovate scales (false perianth); anthers sessile or stipitate on staminal column. Seed cones opposite or in whorls of 3 or 4 at nodes, each cone composed of overlapping bracts; bracts arranged in 2-10 decussate pairs or whorls of 3, red and fleshy at maturity (rarely brown and membranous), proximal bracts empty, most distal bracts subtending an axillary female flower composed of a pair of fused, leathery scales (false perianth) enclosing ovule with a single membranous integument prolonged into a slender, tubular micropyle. Seeds 1-3 per cone, ellipsoid to globose, yellow to dark brown, smooth to scabrous or furrowed (Stevenson 1993, Fu et al. 1999).

Range

Semiarid and arid areas in North America, Mexico, South America, Europe, Asia, and N and E Africa (including Canary Islands) (Stevenson 1993, Fu et al. 1999).

The 35 species in this treatment are distributed as follows:

Their habitats are all described as dry, rocky and/or sandy. A few species occur in grasslands, and for a few species, habitat is not specified.

One species occurs in Argentina and Chile, from Tierra del Fuego to 42° S.

Two species occur in North Africa, one of which also occurs in SW Asia (Saudi Arabia, Kuwait, Israel) and Cyprus.

Twelve species are in the USA (Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Oregon, Texas, Utah, Wyoming) of which 5 species also occur in Mexico (Baja California Norte, Chihuahua, Coahuila, Nuevo León, San Luis Potosí, Sonora).

The remaining 21 species are Eurasian, with focal areas in central Asia (18 species) and around the Mediterreanean (4 species, plus the North African ones). These break out according to country as follows:

China: 14 species (in Gansu, Guizhou, Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, Shandong, Sichuan, Xinjiang, Xizang, and Yunnan)
Pakistan: 9 species
Kazakhstan and Mongolia: 8 species each
Afghanistan: 7 species
Tajikistan: 6 species
Kyrgyzstan, Russia, Uzbekistan: 4 species each
Greece, India, Iran, Nepal, Sikkim, Turkmenistan: 2 species each
Armenia, Bhutan, France, Germany, Hungary, Slovak Republic, Turkey, Ukraine: 1 species each

The New World species mostly occur at elevations of below 2000 m, with a few species reaching as high as 2300 m. The Eurasian species show a much greater elevation range, from sea level to 5300 m (E. gerardiana, the highest gymnosperm species). E. intermedia probably has the greatest elevational range of any single gymnosperm species, ranging from 100 to 4600 m elevation across its vast range.

Big Tree

For most taxa I have found no records of specimen size.

Oldest

I have found no records of specimen age.

Dendrochronology

Although Ephedra does produce growth rings, which in most cases are of roughly annual frequency, the genus has not been used in dendrochronology.

Ethnobotany

The old world species contain variable amounts of ephedrine; curiously it is not present in the New World species, and the psychotropic properties ascribed to "Mormon Tea" and its relatives remain unknown. The oldest drug produced from Ephedra is the Chinese ma-huang, which has been used in Chinese medicine for over 5000 years to treat fever, nasal congestion and asthma. Ma-huang is widely sold in the western world, usually with dubious claims as to its curative values (literature review by Caveney et al. 2001). Ephedra has also been used in the synthesis of methamphetamine (Andrews 1995).

Observations

See the species accounts.

Remarks

Named from the "Greek ep-, upon, and hédra, seat or sitting upon a place; from the ancient name used by Pliny for Equisetum; the stems resemble the jointed stems of Equisetum, the segments of which appear to sit one upon the other" (Stevenson 1993).

"In Ephedra the habit varies greatly even in the same species. Dwarf bushes a few inches high are common (E. distachya, etc.). E. distachya and other species are also represented by tall bushes up to 6 ft. in height, with virgate branches. E. triandra may attain the habit of a small tree with a trunk a foot in diameter. Climbers of the "weaver" type with slender pendent branches are found in E. altissima and E. fragilis: these and other species include forms in which the branches are prostrate.

"Most species, especially in loose soils, spread by means of branching rhizomes which arise from buried nodes of the erect stems; they thus exert a binding effect upon the soils in which they grow. In E. alata, growing in the sand dunes of the Areg formation of Algeria and Tunis, the rhizomes attain a length of several metres and form efficient sand binders. Erect shoots of the normal type arise from the axils of the younger leaf-sheaths. When these shoots are isolated by the breaking or decay of the parent rhizome they differ from seedlings only in the absence of tap-roots" (Pearson 1929).

Citations

Andrews K.M. 1995. Ephedra's role as the precursor in the clandestine manufacture of methamphetamine. Journal of Forensic Science 40: 551-560.

Caveney, Stanley, David A. Charlet, Helmut Freitag, Maria Maier-Stolte and Alvin N. Starratt. 2001. New observations on the secondary chemistry of world Ephedra (Ephedraceae). American Journal of Botany 88:1199-1208. http://www.amjbot.org/cgi/content/full/88/7/1199 (accessed 2006.10.18).

Cutler, H.C. 1939. Monograph of the North American species of the genus Ephedra. Annals of the Missouri Botanical Garden 26:373-427.

Pearson 1929.

Stapf, O. 1889. Die Arten der Gattung Ephedra. Denkschr. Kaiserl. Akad. Wiss., Wien. Math.-Naturwiss. Kl. 56(2): 1-112.