FIGURE 1. Various starch grains.
From the following article:
Starch grains reveal early root crop horticulture in the Panamanian tropical forest
Dolores R. Piperno, Anthony J. Ranere, Irene Holst and Patricia Hansell
Nature 407, 894-897(19 October 2000)
doi:10.1038/35038055
a, A starch grain from manioc recovered from milling stone 42.
b, A starch grain from the putative wild ancestor of manioc, Manihot
esculenta spp. flabellifolia. c, A starch grain from a species
of Dioscorea recovered from milling stone 350. d, A starch grain
from maize from milling stone 42. This type is unique to maize and is found
in Race Jala from Mexico. Scale bar, 5 
m (a, b,
d); 10 m (c).