PREFACE. 
THE area explored by Mr George Forrest during his 1921-22 
expedition included certain parts of N.W. Yunnan, S.E. Tibet 
and 8.W. Szechuan. His collection for those two years con- 
sists of 3924 numbers of which a large proportion is represented 
by the genus Rhododendron. The present catalogue is an 
enumeration of the plants collected excluding Rhododendron. 
The materials of the latter genus have not yet been fully worked 
out and will require considerable time for their elucidation. 
The majority of the specimens were collected within the con- 
fines of Yunnan; the remainder in those regions of Szechuan 
and Tibet which border on N.W. Yunnan. The areas lie be- 
tween lat. 24° 35’ N. and 28° 48’ N. and between long. 97° 35’ 
E. and 101° 6’ E. 
This fifth expedition supplements the work carried through 
on previous journeys, and extends the area botanically explored 
further west and north. On the west Mr Forrest went beyond 
the Salwin-Kiu Chiang divide, while on the north he extended 
his survey along the same divide, as well as along the Mekong- 
Salwin divide. Considerable collections were made in the 
Salwin valley up to lat. 28° 48’ N. 
The Royal Botanic Garden, Edinburgh, owes the possession 
of this valuable collection to the generosity of . 
Williams, Caerhays Castle, Cornwall, and of Mr Reginaid 
Cory, Duffryn Castle, Cardiff, for whom Mr Forrest undertook 
these two years of botanical exploration. . 
