Interesting question. I have three or so answers; I feel like my
answer to kernel of corn is a bit weaker than that of wheat
berry, but I guess you can be the judge of that. Kernel of corn
The modern appearance of what we Americans know as corn (maize)
is deceiving as to its history. As you may or may not know,
maize is not a natural plant, and could not survive in the wild
by itself -- it was originally domesticated by pre-Columbian
Americans over the period of a 1000 or so years from its natural
ancestor teosinte. It cannot reproduce in the wild, primarily
because it has no good vector of reproduction; plants, being
sessile creatures, and being intensely competitive for space,
often have to adopt "natural" vectors to transport their seeds
from their birthplace far and wide so their progeny have the
best chance to survive. Most fruits, sugary and pleasant
smelling, have adopted animals as their vector to transport
their seeds; teosinte, and other grains of the grass family,
adapted to drier, more arid locale