TO 
Dh ASA: GRAY, 
PROFESSOR OF BOTANY 
IN THE 
UNIVERSITY OF NEW CAMBRIDGE, MASSACHUSETTS, 
WHOSE RECENT SOJOURN AT KEW 
HAS BUT TENDED TO INCREASE THE MUTUAL REGARD AND ESTEEM 
INDUCED BY A FORMER VISIT AND BY LONG CORRESPONDENCE, 
The Present Golume 
IS DEDICATED, 
BY HIS FAITHFUL AND AFFECTIONATE FRIEND, 
bg 
THE AUTHOR. 
‘Roya GarDENs, Kew, 
Dee, Ist, 1851. 
