Notes . 
375 
plant-organ towards the point, not where it will find a minimum 
or maximum of moisture, but where it will, within certain limits, 
transpire most or least. 
LEO ERRERA, Brussels. 
BOTANICAL NOTES. 
No. i. ON THE THORNS OF RANDIA DUMETORTJM, 
LAM. — Randia dumetorum is a Rubiaceous plant widely distributed 
in tropical East Africa, India, the Malayan Archipelago, up to China, 
including Formosa and Hong Kong. The plant is very common 
on Dane’s Island, Whampoa, where my observations were made. 
Position and arrangement of the thorns. — The leaves of this plant 
are opposite as in most Rubiaceae. In the axil of each leaf is a 
branch, or bud, directly above which a thorn frequently occurs ; so 
the thorns are supra-axillary. As a rule there is a distinct, often 
considerable, difference in the size of the two leaves at a node. 
The smaller leaf not uncommonly decays and drops off early in 
life. The thorn above this leaf is invariably inserted closer to the 
leaf-axil than is the thorn above the larger leaf. This is shown 
in the Fig. i, in which l.l. and s.l. are the stalks of the large and 
small leaves respectively, and b.h. are the axillary buds. Thorns 
never occur in relation with the first pair of leaves of a branch, 
and they are occasionally not developed in connection with pairs 
of leaves higher up the branches; frequently a thorn occurs above 
only one of the leaves at a node, in which case it almost always 
is situated above the larger leaf. 
Morphological Significance of the Thorns. — As far as the position 
of the thorn is concerned it might be a trichome, an emergence, 
or an accessory branch. It is not very exceptional to find in 
plants a protective outgrowth of the cortex above the axillary bud 
