93 
With the increase of the collections, it is becoming more difficult 
to obtain additional distinct and hardy species. Further, in the 
case of several groups, the space allotted is fully taken up. 
Maps OF COLLECTIONS 
With the increase of the number of species and varieties, keep- 
ing record of the plants by mapping becomes more necessary. 
Figure 9 shows a map of the genus Forsythia. We have still 
many trees and shrubs on the grounds which have never flowered. 
Thus the exact name may remain undetermined for years. Mr. 
J. Pollio has prepared on tracing cloth three large maps of the 
systematic section of the Garden. One shows the location of 
genera of trees, another genera of shrubs, and the third plant 
families represented on the grounds. 
List oF TREES AND SHRUBS 
The Kew Hand List of Trees and Shrubs, 3d edition, was pub- 
lished in 1925; this list has been very useful to us. Its arrange- 
ment by the Bentham and Hooker system makes it inconvenient 
en, arranged by the Engler system. With Mr. Rehder 
— 
for our garc 
of the Arnold Arboretum I have been making a checklist of hardy 
trees and shrubs based on his Manual. In the spring and again 
in the fall 1 visited the Arboretum for consultation about details. 
This list is now approaching completion. It is intended to include 
the names accepted by the New International Rules as well as the 
names used in the Kew Hand-List of Trees and Shrubs, Standard- 
ized Plant Names, Gray’s Manual, Schneider’s Handbuch and a 
few other important publications. There may be some question 
as to how rapidly we should attempt to proceed in changing names 
long established in our garden and in botanical literature. Pos- 
sibly the question of “ specific names to be conserved” (nomuna 
specifica conservanda) may come up again at the next Botanical 
Congress. Before then the new International Horticultural List 
will be available. In any case, a hand list of species is needed 
in gardens in making records about the plants. In order to plan 
for the future we must know readily what we have, compared to 
_— 
what we might have, in any group. 
