Dear Silvia - and others who might want the same information:

Elvia Esparza Alvarado is a botanical artist in Mexico and gave an
excellent talk on the history of botanical art in Mexico at our Washington,
D.C. GNSI annual meeting.  I suggest contacting her:

Instituto de Biologia, UNAM
APDO Postal 70-153
Mexico City, DF 04510
Mexico

h:  011-525-622-5689
w:  011-525-622-5687    I suspect one of these numbers is a fax and not a
home number, but this is how they are listed in the GNSI Directory.

Alice Tangerini and Marion Sheehan also might have book recommendations.
They both are in the GNSI Directory.

Best wishes,

Elaine