> The cross-pollination
> info is particularly precise.
Another example of this is the case of squashes. The pepo, maxima,
moschata, mixta, etc varieties will not interpollinate. Squash flowers are
big and a
single insect will easily become laden from one blossom. By planting the
various species in alternation, the likelihood of an insect making it from
one to
another is minimal.