Pinus (Pinaceae)


Pinus contorta
Trees of the Pacific Northwest


Pinus elliotii
APMRU Gretchen Jones


Pinus echinata
APMRU Gretchen Jones

Plant:
World-wide distribution, nearly 100 species, narrow, persistent leaves (needles) bound in fascicles, on branches borned in distinctive "whorls" on the trunk. Female cones 5 - 50 cm with thick woody scales. Male cones 1 cm. microsporophylls peltate. The Pinus pollen type is a champion of long distance dispersal, and is found in most fossil samples from the Northern Hemisphere.

Pollen light micrograph:
pine.gif Pinus is a bisaccate (or vesiculate) pollen grain consisting of a body with two latarally-placed bladders (sacca, vesicles). Its maximum dimension is generally 50 - 75 µm. Two pine subgenera Haploxylon and Diploxylon are differentiated by the presence or absence of bumps (B) on the membrane between the bladders (Ueno, 1960). The outer junction between the body and the bladder (A) is acute, except for Pinus aristata, which also has a wavey (W) outer bladder. A raised, irregular frill (F) is characteristic of Pinus ponderosa, but a ridge (R) along the boarder with the membrane is more common on Pinus contorta.

Pollen scanning electron micrograph (SEM)
The "reticulate" pattern of the bladders is shown to be internal, consisting of minute "blisters" or alveoli. The scultpure of the of the body is very rough.

Production and Dispersal:
Pine pollen is very abundant and very widely distributed

Preservation:
Pine pollen is well preserved, but the membrane between the bladders is usually ruptured, preventing the identification of Hap. vs. Dip. subgenera.

Fossil Occurrence:
Bisaccate conifer pollen occurrs from the late Paleozoic onward. However, plant fossils (leaves, cones) of the Pinaceae first appear in the middle to late Mesozoic.

References:
    Bagnall, C. R., Jr. 1974.
    Pollen morphology of Abies, Picea, and Pinus species of the U.S. Pacific Northwest using scanning electron microscopy. Ph. D. dissertation, Washington State Univ.

    Bagnall, C. R., Jr. 1975.
    Species identification among pollen grains of Abies, Picea, and Pinus in the Rocky Mountain area (A scanning electoron microscope study). Rev. Palaeobotany Palynology 19: 203-220.

    Hansen, B. S. and Cushing, E. J. 1973.
    Identification of pine pollen of late Quaternary age from the Chuska Mountains, New Mexico. Geol. Soc. Amer. Bull. 84: 1181 - 1200.

    Jacobs, B. F. 1985.
    Identification of pine pollen from the Southwestern United States. AASP Contribution Series 16:155-168.

    Mack, R. N. 1971.
    Pollen size variation in some western North American pines as related to fossil pollen identification. Northwest Science 45: 257 - 269.

    Ting, W. S. 1966.
    Determination of Pinus species by pollen statistics. Univ. Calif. Publ. Geolog. Sci. vol. 58.

    Ueno, J. 1960
    On the fine structure of the cell walls of some gymnosperm pollen. Biological Journal of the Nara Women's Univesity. 10: 19 - 25.

    Whitehead, D. R. 1964.
    Fossil pine pollen and full-glacial vegetation isn southeastern North Carolina. Ecology 45: 767-777.
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Owen K. Davis 12/99