On the Distribution, Structure, and Function of 
the Tentacles of Roridula. 
BY 
A. NINIAN BRUCE, B.Sc. 
With Plates XX.-XXI. 
The genus Roridula' is usually included in the family of the 
Droseracez, although doubts are now prevalent as to its right to 
this position. Itis confined to South Africa. It includes two 
species of small shrubby plants, &. Gorgonias, Planch., and R&R. 
dentata, Linn. These resemble each other closely in outward 
appearance, particularly in the possession of numerous tentacles 
distributed over their leaves and stem. The arrangement, 
structure, and function of these tentacles has not been as yet 
fully investigated, and the following brief account of them is 
the result of the examination of (and experiments upon) living 
plants grown in the Royal Botanic Garden, Edinburgh, and ot 
material preserved from these. 
LEAF OF RORIDULA GORGONIAS. 
The leaves of Roridula Gorgonias are closely set along the 
stem. 
The leaf is long and narrow; its maximum length about 6 
cm., its greatest width, just above the base, is about ‘25 cm. 
This width remains fairly constant through about the lower 
third above which the leaf begins to taper to the apex, where it 
ends in a single large tentacle. In its lower part dorsiventral it 
becomes radial and quite cylindric before it passes imperceptibly 
into the tentacle (Fig. 1). The surface is covered by numerous 
‘From ros, roris, dew, after the glistening drops of secretion found on the 
ends of the tentacles. 
[Notes, R.B.G., Edin., No. XVIL., April 1907.] 
