PREFACE. ix 
quire much explanation. As the synonymy is 
one of the most difficult and perhaps important 
parts of the subject, it has of course received 
particular attention. But I have rarely been 
very anxious about the synonyms of botanists of 
an earlier date than the time of Linnzus, on ac- 
count of the extreme uncertainty of the precise 
plants which they intended. The work might 
have been extended to a much greater length, 
had I not aimed at avoiding to repeat what has 
been previously said by others, except so far as 
was necessary to make myself intelligible. In 
marks and abbreviations the plan laid down by 
M. De Candolle, in his excellent Regni vegeta- 
bilis systema naturale has been my guide, but 
with some slight deviations. 
To the noble library and inexhaustible Bo- 
tanical treasures of the Right Honourable Sir 
JosepH Banxs, with that unexampled liberality 
for which their illustrious possessor has been 
ever celebrated, I have been allowed the freest 
access. To these I am almost entirely indebted 
for the numerous and highly interesting species, 
either altogether new, or hitherto imperfectly 
known, from the hotter countries of Asia, Africa, 
and North America. The authentic specimens 
preserved there from Jacquin, Pallas, and others, 
with those of the Hortus Kewensis, have enabled 
me to determine many of their synonyms with 
precision. To the pee eee of Aylmer Bourke 
