EXPERIMENTAL ESTIMATES OF POLLEN SEDIMENTATION VELOCITY
Numerous attempts have been made to measure sedimentation velocity of pollen grains and spores directly, using a variety of apparatus.
COMPARISON WITH THEORETICAL ESTIMATES OF SEDIMENTATION VELOCITY
We have no objective basis for identifying any of the experimental studies of sedimentation velocity as authoritative; none of the sampling apparatus were calibrated using standards (e.g., microspheres of known dimension and density).
The overall good fit between measured and predicted estimates of sedimentation velocity [ILLUSTRATION FOR FIGURE 5 OMITTED] provides a basis for some confidence in the measured values of Eisenhut (1961) and especially Durham (1946).
2) for several important taxa (Picea, Pinus, Quercus, Betula, Alnus) owing to measurement uncertainties in sedimentation velocity [ILLUSTRATION FOR FIGURE 6 OMITTED].