152 
POLLEN PRESENTATION 
differing from it (in floral characters), in the absence of a pappus and of long, 
si,lky hairs covering the achenes. 
The ray-florets are all neuter, as in Cryptostemma. 
Arctotheca is quite similar to Cryptostemma in the method of pollen pre- 
sentation, and the styles are also irritable. Indeed the only important differ- 
ence observed between the two genera was that in Arctotheca the expanded 
styles are not so sensitive to touch as those of Cryptostemma. Plate IX. 
BIBLIOGRAPHY. 
von Minden, M., 1901. Reizbare Griffel von zwei Arctotis-Arten. Flora, lxxxvui, p. 238. 
Small, J., 1915. Preliminary observations on the pollination mechanism of Arctotis 
aspera, Linn. New Pbyt. xiv, p. 216. 
A NOTE ON “DOUBLING” IN ERICA VENTRICOSA , 
Thunb. 
By R. GLOVER. 
Specimens of Erica ventricosa, Thunb., found in the neighbourhood of 
French Hoek and sent to the late Dr Pearson by Dr de Villiers, shew the first 
case, which has come under our notice, of “doubling” in the genus Erica. 
This is an example of Petaloidy, which according to W. C. Worsdell is 
the commonest form of “doubling” produced as a result of cultivation. 
The drawings (Plate XIII A) shew the transition stages from stamens to 
petals. None of the stamens was perfect nor did any of the petaloid series 
shew either 4 or 8 parts but varied from 6 to 7 parts. 
