610 Transactions of the Royal Society of South Africa. 
and close-grained, and, in a great many species, of high specific gravity. The 
species are generally slow-growing. It is doubtful whether the rings in the 
wood are always, properly speaking, annual rings. A species may be in 
full growth at the end of summer, stop for a short time in mid-winter, begin 
again in spring, and stop for a short time in midsummer. This is certainly 
very noticeable in such trees as the Orange and Pinus insignis, as cultivated 
in Natal. 
The total number of Mega-mesophanerophytes is cir. 95. A number of 
lianes of the ropy, woody type are included. They are the familiar 
monkey-ropes " that are so abundant in the forests of Natal. The number 
included in the class Mesophanerophytes might easily be increased, but the 
others are included in the next class — Microphanerophytes — as being more 
often under than over 8 metres. In Warming's system the lianes are 
separated from the trees and shrubs — in fact, they form one of his six 
main classes of growth-forms. This is undoubtedly more natural, but as 
far as protection against the adverse season is concerned, there is no reason 
why they should be separated. By including them with the trees and 
shrubs we avoid a further difiiculty in that many woody lianes, in the 
absence of support, grow as shrubs or small trees — e.g. Scutia commersonii, 
Balhergia ohovata, and others. 
There are certain general features of the Mega-mesophanerophytes that 
may be summed up as follows : 
(1) Great variation in size and form exhibited by the same species, 
depending on differences in the environment, particularly (a) the differences 
between Sand-dune Bush, other coast-bush, and inland-bush ; (b) the 
differences between open Eocky Hillside, Thorn Yeld, Stream Bush, and Close 
Bush. The details concerning each of those environments have been given 
by the writer in former papers (1, 2) and need not be repeated here. The 
point on which emphasis is desired to be laid is that many species in this 
class exhibit great plasticity or power of adaptability to widely differing 
environmental conditions. 
The examples of lianes growing as trees and shrubs may be requoted, 
and, in addition, the following species illustrate this point : 
Kiggelaria africana, Toddalia lanceolata, EJcehergia capensis, Trichilia 
emetica, Apodytes dimidiata, Pteroxylon utile, Rhus laevigata, Scholia la.ii- 
folia, Milletia caffra, Alhizzia fastigiata, Plectronia ohovata, Nuxia congesta, 
Myrsine melanophleus, Cordia caffra, Celtis Jcraussiana, Ficus capensis. 
(2) Variation in foliage of the same species depending on the same 
differences in environment as the last. The leaves of certain species are 
more succulent nearer the coast. The leaves of others are larger nearer the 
coast, or the shape of the leaf may change from the coast, inland. There is 
variation also, according to whether the tree grows isolated (Thorn Veld, 
Rocky Hillside), semi-isolated (Stream Bush), or in dense forest. 
