Mite-induced Galls of Hoheria sexstylosa — Arnold 505 
FIG. 4. Longitudinal section through a "pouch meristem,” X 250. m, section through portion of a mite; 
e, epidermal hair; v, vascular strand differentiating; pm, inner layer of pouch meristem. 
the first three or four weeks, but galls derived 
from flower buds remain firmly attached by the 
pedicel, often for several years. It would seem 
that the tendency to galling of flower buds 
rather than of leaves represents an evolutionary 
adaptation favouring the mites. 
Furthermore, the mode of enclosure of the 
mite colonies by the activity of the "pouch 
meristem” may also be regarded as an evolu- 
tionary adaptation shielding the mite colony 
from the exterior. The majority of eriophyid 
mites are said to be vagrants on the surface of 
foliage or in galls of other species of plants 
(Evans, Sheals, and Macfarlane, 1961). 
While one can readily enough draw a paral- 
lel between the activity of the "pouch meristem” 
in Hoheria galls and the shoot growing point of 
angiosperms, it could also be claimed that there 
