612 Transactions of the Boyal Society of South Africa. 
Examples : Xymalos monospora, Ocotea hullata, Kiggelaria africana, 
Rhus laevigata, Milletia caffra, Milletia sutherlandi, Nuxia congesta. 
(8) The EFFECT OF EXPOSURE, particularly along the seashore, in causing 
branching from the base, is seen in Sideroxylon inerme, Mimusops caffra, and 
others. 
Taken as a whole, the class of Mesophanerophytes show certain pro- 
gressive adaptations to unfavourable conditions, of which the most important 
are, decrease in size (which is often very marked), increase in succulence and 
other xerophytic characters in the foliage, increase of pubescence, a tendency 
towards becoming deciduous, increased branching from the base and forma- 
tion of coppice shoots, which often replace the main stem, a development 
of thick bark, and spinosity. 
Not only are those features and tendencies illustrated by the species 
making up the whole class, but also by the individuals of single species, 
often in a most striking manner. Among unfavourable conditions we must 
include not only the adverse conditions of the winter dry season, but also 
exposure, proximity to the sea, and other factors which serve to differentiate 
the various habitats at all seasons of the year. 
While we use the degree of protection of the buds or resting shoot apices 
as the main character serving to determine the class as a whole, we are able 
to use any of the other features mentioned to serve as a basis for further 
subdivision. For instance, we might choose the somewhat artificial distinc- 
tion of thickness in the bark, and arrange the species in a series accordingly. 
Or we might form subgroups as follows: Evergreen, semi-deciduous, 
deciduous. 
Whatever system of subdivision might be adopted, the variability of 
single species would be found very troublesome, and the class, as a whole, 
is not so large that any subdivision is necessary. At the same time, it is 
necessary to notice as clearly as possible the various tendencies exhibited by 
the class. This must be our excuse for presenting them in tabulated form 
above. 
MICEOPHANEEOPHYTES. 
It will be obvious that no sharp line of distinction can be drawn between 
any of the groups of Phanerophytes or other classes of growth-forms. Such 
forms as Celtis hraussiana or Myrshie melanophleus might be classed as 
Nano-, Micro-, or Mesophanerophytes, according to circumstances. Many of 
those included in the list of Mesophanerophytes only occasionally reach the 
necessary dimensions. On the other hand, a few of those included among 
Microphanerophytes sometimes exceed 8 metres (26 ft.) in height. There 
are numerous instances, again, of the same species assuming different 
growth-forms — shrub, tree, or woody liane, e.g. Dalhergia ohovata. In fact, 
