138 
Transactions of the Boyal Society of South Africa. 
the variegations are not usually accompanied by any differences in thick- 
ness or structure, other than the distribution of plastids and pigments. As 
far as the writer is aware, no case similar to that now described has been 
previously recorded. 
It is quite conceivable that the well-known leaves of Monstera (also 
belonging to the Aracece) may have been derived from a type of leaf 
similar to that of Bichardia alho-maculata. In Monstera portions of the 
leaf lamina dry up and break away entirely, and an epidermis is then 
formed round the edges of the hole thus produced. 
In one respect the leaf of B. africana has been found to be very 
different from that of B. alho-maculata, namely, in the size of the inter- 
cellular spaces in the spongy parenchyma. In B. africana these are very 
large and numerous, and the most conspicuous feature in a section of the 
leaf, being bounded only by trabeculae, in the form of chains of mesophyll 
cells ; in B. alho-maculata, on the other hand, the intercellular spaces, as 
seen in section, seldom exceed the dimensions of a single mesophyll cell, 
and are not at all a conspicuous feature of the anatomy. In other respects 
the leaf structure is very similar in the two species, and shows no other 
noteworthy peculiarities. 
My thanks are due to Mr. Z. J. de Beer, who prepared the sections 
from which the photographs were taken. 
