Classification

ephedra
phylogeny

images





Ephedra is a shrubby plant
in the division
Gnetophyta.



Classifying Ephedra

Among the Gymnosperms, the Ephedra is one of three genera in the eclectic Division Gnetophyta, bearing slight resemblance to any of the relatives except that they are all resticted in distribution and are not widely cultivated. Only Ephedra is native to the United States, where it grows as a shrub or vine in Texas, New Mexico, Arizona, California, and Nevada. It has, however, been known to reproduce so far North as Boston, Massachussetts; Marburg, Germany; and Cambridge, England.

Ephedra is certainly not the most glamorous plant in the world, but at least vegetatively, with its jointed, photosynthetic green stems, it resembles Equisetum (an herbaceous vascular cryptogam in the Division Arthrophyta). Most species of Ephedra are dioecious, and cross-fertilization may occur in some Texas species. Among Ephedra and its relatives Gnetum and Welwitschia, Ephedra is considered to be primitive since its female gametophytes produce archegonia. The other gnetophytes, Gnetum and Wlwitschia, do not develop archegonia; instead, the free eggs are fertilized as in angiosperms. An interesting feature of all gnetophytes is the presence of vessel elements in their xylem tissue. Most flowering plants contain vessel elements, too, providing evidence to some botanists that the Gnetophyta might have been ancestral to angiosperms. Although all three gnetophyte groups are very different; all of the Ephedra resemble each other closely, so the differences in morphology are not obvious to an untrained eye.

Ephedra is also known by other names. Collected from harvests in the Southwest deserts of the United States, it is called Mormon tea or Brigham tea, a collective term for those endigenous to that region. The early settlers used to dry the stems and brew from them a stimulant beverage. American versions of the genus are have also been referred to as "joint fir", due to the jointed stems, nodes, and internodes that resemble the Arthrophyta. If it is sourced in Asia, then it is referred to as Ma-huang. An historical plant in Asia, Ma-huang is first mentioned in the classic Chinese herbal of the Divine Plowman Emporer, Shen-Nong's Ben Cao Jing, which survives a list of 365 herbs from the first century A.D. This is the basis of the modern Chinese herbal medicine. Both E. equisetina and E.sinica are Asian species.

Medical Botany Home

If these features don't seem to be working, you should download the JavaScript-enabled Netscape Navigator.