It is interesting to note that many of the plants identified from their
megascopic remains by Walton C. Galinat are likewise represented in the
pollen flora (e.g., _Allium_, _Quercus_, _Juniperus_ and chenopods).
As Galinat has also identified several fragments of _Zea Mays_, it was
hoped that pollen of _Zea_ might be found in some of the oldest levels.
Unfortunately, none of the fossil grass pollen can be definitely
identified as that of _Zea_. It seems obvious that the three largest
grass grains (over 70ₘ) are too large to be _Tripsacum_, but whether
they represent _teosinte_ or _Zea_ can not be established. The pore
of two of these was obscured by detritus, and that of the third was
greatly distorted. Thus no ratio could be established.
The remainder of the grass grains seem to fall within the limits of
the genus _Tripsacum_ (size extremes 33.6ₘ to 64ₘ, and ratio extremes
1:3.0 to 1:4.8), although the pore-axis ratio of some appears to be too
large. However, the possibility must be left open that these smaller
grains might not be _Tripsacum_. As yet there is very little pollen
size data available for the grasses of North America. Geisler (1945)
has measured pollen from 32 species and of these, _Zizania aquatica_
has the largest grains (range 38ₘ-50ₘ). It is important to note that
she did not employ acetolysis, so that this range is on the small
side. In Europe, Firbes (1936) has presented pollen size data for
103 species of grasses, and of those he studied, _Avena_, _Secale_,
_Triticum_, _Hordeum_, and _Elymus_ possess pollen as large as that of
_Tripsacum_. Hence it would appear to be necessary to study intensively
the pollen of most of our native grasses in order to establish size and
other morphological criteria for identifying the smaller LoDaisKa grass
pollen.
As the preservation is distinctly better in the lower levels of the
deposit, a careful and detailed pollen analytical investigation, with
recourse to adequate reference material might be profitable.