Cxliv PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 
a similar effect. Hence the deeper coloration would be due to 
the enhancing the assimilating powers of the foliage. The case 
of Viola calaminaria was mentioned, a species which absorbed 
salts of zinc from growing in localities where the carbonate of 
this metal was abundant ; and Dr. Miiller alluded to the 
peculiarity that it did not appear solely as an accidental in- 
gredient to the plant, but that it actually entered into its 
constitution. Mr. Wilks was good enough to place some Apple 
trees at the disposal of the Committee for experimental purposes, 
and it is also proposed to use white Hyacinths as soon as the 
procedure shall have been determined upon by Dr. Miiller and 
Dr. Russell. The Committee will be glad to receive information 
from any correspondent who may have had experience in the 
changes of colours through the action of the soil in any way. 
Cypripedium, Origin of the Slipper. — Dr. Bonavia gave the 
following possible morphology of the labellum of this Orchid : — 
In Canada a wild Cypripedium (Selenipedium) acaule has a 
natural slit down the median line on the front of the slipper. 
This suggests that the slipper may have been originally an open 
labellum, like that of other Orchids, while the incurving of the 
edges and their final fusion made a slipper. To-day at the 
meeting I saw a Cypripedium with its slipper open. This may 
have been an accidental rent ; but, supposing this to be so, the 
fact that the rent occurred down the median line shows a line of 
cleavage there. Moreover, in several there was a distinct line 
down the middle, and in some the veins converged towards that 
line ; in others both the veins and median line were obliterated.'* 
FRUIT COMMITTEE. 
July 9, 1895. 
Dr. Robert Hogg in the Chair, and eleven members present. 
Awards Recommended:— 
Silver Gilt Kniyhtian Medal. 
To Messrs. James Veitch Sons, Chelsea, for a large 
collection of fruit containing thirty-nine varieties of Cherries, 
two of Raspberries, four of Currants, ten of Gooseberries, with a 
