The World Flora Online

Shrubs or vines , erect or clambering, Equisetum -like, dioecious (very rarely monoecious). Bark gray to reddish brown, cracked and fissured. Branches generally many, terete, whorled to fascicled, finely longitudinally grooved, internodes 1--10 cm. Roots generally fibrous. Leaves simple, opposite and decussate or whorled, scalelike, connate at base to form sheath, generally ephemeral, mostly not photosynthetic; resin canals absent. Pollen cones compound, 1--10 in whorls at nodes; each compound cone composed of 2--8 sets of opposite or whorled membranous bracts, proximal bracts empty, each distal bract subtending a small cone composed of 2 basally fused bracteoles subtending a sporangiophore bearing 2--10(--15) sessile to long-stalked, bilocular, apically dehiscent, pollen-producing microsporangia. Pollen prolate, with 6--12 longitudinal furrows, not winged. Seed cones compound, 1--10 in whorls at nodes of twigs; each compound cone sessile or on short to long peduncle, composed of 2--10 sets of overlapping, opposite or whorled, membranous or papery to fleshy bracts, proximal bracts empty, most distal bracts subtending 1 axillary cone composed of a pair of fused bracteoles enclosing a single-integumented ovule with integument projecting as tube from bracteole-envelope, envelope forming a leathery "seed coat" that is shed with seed. Seeds 1--2(--3) per compound seed cone, yellow to dark brown, smooth or furrowed; cotyledons 2.

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Shrubs, subshrubs, or herbs, dioecious, rarely monoecious; stems erect, procumbent, or occasionally climbing, jointed, much branched, photosynthetic; branchlets opposite or whorled, green, terete, longitudinally grooved. Leaves opposite or in whorls of 3, scalelike, basally ± connate and reduced to membranous sheaths, generally ephemeral, mostly not photosynthetic; resin canals absent. Cones terminal or axillary, ovoid or ellipsoid. Pollen cones solitary or clustered at nodes, each cone composed of membranous bracts arranged in 2-8 decussate pairs or whorls of 3; 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 or 2(or 3) per cone. Cotyledons 2. Germination epigeal. 2n = 14*, ?24*, 28*, ?36*, 56*.

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SELECTED REFERENCES

Markgraf, F. 1926. Ephedraceae. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien..., ed. 2. Leipzig and Berlin. Vol. 13, pp. 409--419. Meyer, C. A. von. 1846. Versuch einer Monographie der Gattung Ephedra. Mém. Acad. Imp. Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt. Sci. Nat. 5(2): 225--298. Kubitzki, K. 1990. Ephedraceae. In: K. Kubitzki et al., eds. 1990+. The Families and Genera of Vascular Plants. Berlin etc. Vol. 1, pp. 379--382. Parlatore, F. 1868. Gnetaceae. In: A. P. and A. L. P. de Candolle, eds. 1823--1873. Prodromus Systematis Naturalis Regni Vegetabilis.... Paris etc. Vol. 16, part 2, pp. 352--359. Stapf, O. 1889. Die Arten der Gattung Ephedra. Denkschr. Kaiserl. Akad. Wiss., Wien. Math.-Naturwiss. Kl. 56(2): 1--112.

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