Aztec ethobotany questions.

[Coon, Brad]

Can anyone suggest a good work in English or Spanish preferably dealing =
with
Nahua ethnobotany. I am most=20
interested in the period at the time of contact but not exclusively so.

I am particularly interested in one species.  Luis Cabrera's book
"Diccionario de Aztequismos" mentions a plant called 'mechoac=E1n' used =
as a
purgative.  I would welcome any and all references to it particularly =
in the
Florentine Codex.
Many thanks,
Brad Coon
bcoon at montana.edu