Materials and Methods

Whenever possible, at least ten specimens from each species were measured for the appropriate dimensions. In most cases, measurements were made from digital images using the morphometrics package ImageJ (available via download at http://rsb.info.nih.gov/ij/). In a few cases, measurements were made using an ocular micrometer in the microscope.

The atlas includes 121 species, 110 genera, and 63 families of plants. Complete descriptions are arranged alphabetically by family, with pteridophytes first, followed by monocotyledonous plants, then dicotyledonous plants. Nomenclature follows USDA National Plants Database (USDA, NRCS, 2004). Photographic plates are arranged morphologically to facilitate identification. Amb or overall grain shape is first defined, followed by shape classes (i.e., prolate, oblate) as originally defined by Erdtman (1943, 1952). The shape classes are based on measurements of the polar axis (P) and equatorial diameter (E) and the resulting P/E ratio (see glossary). Mean dimensions are provided, followed by minima and maxima in parentheses. Aperture and sculpture characteristics for all described species are summarized in Table 4. In each description, exine thicknesses are given exclusive of positive sculpture. A glossary of palynological terminology is provided in Appendix 1.

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Go to Table 4