Ephedra (Ephedraceae)

Ephedra antisyphilitica(l) E. coryi(r) © S.Ickert-Bond


Ephedra viridis UofAz 2409
UofAz Palynology

Ephedra nevadensis
Ephedra nevadensis SEM C.Drew
UofAz Palynology

Plant:
Ephedra (joint-fir, Mormon tea) is characteristic of arid regions of the Northern hemisphere. The plant consists of green cylindrical stems, with tiny leaflets at its nodes. Fertilization is unique in that the egg also produces a tube that unites with the pollen tube, and two egg nuclei are fertilized. However the second egg nucleus degenerates and does not produce tissue like the endosperm of angeosperms. Ephedra pollen is particularly abundant (25%) in modern pollen samples from the Grand Canyon (King and Sigleo, 1973).

Pollen light micrograph:
drawing Ephedra (joint-fir, Mormon-tea) has the polyplicate pollen type, characterized by a pointed-oval shape and longitudinal ridges. This pollen type is found in the living Ephedra and Welwitchia of the gymnosperm Class Gnetophyta and in many extinct forms beginning in the Paleozoic. The key characters in distinguishing the pollen of species of Ephedra are the number of ridges, the shape of the ridges (rounded vs. sharp), the branching pattern between the ridges, and the size of the grain (35 - 70 µm long; Steves and Barghoorn, 1959).

Pollen scanning electron micrograph (SEM)
The wall of Ephedra is simple, so the SEM closely resembles the light micrograph.

Production and Dispersal:
Produced in moderate abundance, but very widely distributed. High percentages (45%) are recorded for the lower Grand Canyon.

Preservation:
Good preservation.

Fossil Occurrence:
Ephedra is an member of the ancient gymnosperm Class Gentophyta, whose foliage is present in the fossil record from the Triassic onward, associated with the plant fossils Piroconites and Masculostrobus. Ephedra pollen is associated with arid-vegetation pollen assemblages from the Miocene onward (Barnosky, 1984; Davis and Moutoux, 1998).

References:
    Barnosky, C.W. 1984.
    Late Miocene vegetational and climatic variations inferred from a pollen record in Northwest Wyoming. Science. 223: 49-51.

    Davis, O.K. and Moutoux, T.E. 1998.
    Tertiary and Quaternary vegetation history of the Great Salt Lake, U.S.A. Journal of Paleolimnology. 19 (4): 417-427.

    King J. E.,W. R. Sigleo. 1973.
    Modern pollen in the Grand Canyon, Arizona. Geoscience and Man,7:73-81.

    Steeves, M.W. and Barghoorn, E.S. 1959.
    The pollen of Ephedra. Journal Arnold Arboretum. 40: 221-259.

Links
KEY TO POLYPLICATE POLLEN
from Kapp Online*

Pollen of this type is restricted to the Gymnosperm genera Welwitschia (southwestern Africa) and Ephedra in the Gentales. Only two basic types are distinguished in this key, those with branched and those with straight furrows.

    1a Furrows branched (Ephedra nevadensis type)
    1b Furrows straight or obscure, not branched (Ephedra torreyana type)
* Kapp Online is an ongoing project associated with the publication
    Kapp, R.O., Davis, O.K., and King, J.E. 2000.
    Ronald O. Kapp's Pollen and Spores, Second Edition. American Association of Stratigraphic Palynologists 279 p.
    Contact Vaughn M. Bryant, Jr. Email vbryant@tamu.edu Phone: (979) 845-5242/845-5255; Fax: (979) 845-4070.

Owen K. Davis revised 7/01