PREFACE. 
THE difficulty of procuring in America, books 
relative to natural families, has induced the per¬ 
son who in this summer has given a course of 
elementary and philosophical botany in Philadel¬ 
phia, to offer to his subscribers instead of a com¬ 
mon syllabus , this reduction to natural families of 
all the American genera of plants, contained in 
the late Dr. Muhlenberg’s Catalogus Plantarum 
America; Septentrionalis. This reduction he be¬ 
lieves may prove an useful appendage, and a sort 
of complement to that work, which, for a while at 
least, will be the manual of American botanists. 
In proportion as they are acquainted with Ame¬ 
rican genera, they will by this mean obtain the 
feeling of their natural affinities, which generally 
become very sensible when once indicated to those 
who already know the plants. Such advantage he 
believes to be far superior to that which they could 
derive from a simple enumeration of heads of the 
principal matters which have been treated in the 
course. It will be a better preparation to the deep 
knowledge of natural affinities, which in future 
