xxvi Transactions of the Royal Society of South Africa. 
Ordinary Meeting. 
August 18, 1915. 
The President, Dr. L. Peringuey, was in the Chair. 
The Minutes of the previous Meeting were confirmed. 
Mr. F. W. Pettey and Mr. J. Figdor, L.D.S., were elected to member- 
ship. 
The following communications were made : 
*' The G-rowth Forms of Natal Plants." By J. W. Bews. (Communi- 
cated by Prof. H. H. W. Pearson.) 
The author gives a detailed description of his work on the growth forms 
of Natal plants. The investigation of the growth forms of plants in relation 
to their environment is being recognised as a very important, if not the most 
important, branch of Plant Ecology. The study of the various plant com- 
munities and their determination by the environmental factors presents a 
more general aspect of the subject, and has hitherto perhaps on the whole 
received more attention from plant ecologists, though, of course, it includes a 
certain amount of the study of the separate growth forms. It is, however, 
in the more detailed study of the " epharmony " of the species of plants that 
a deeper insight is gained into the cause and effect relationship existing 
between the environment and plant life. 
" The South African Eust Fungi." 1. The Species of Puccinia on Com- 
positae." By I. B. Pole-Evans. 
Descriptions and accompanying notes are given of the species of Puccinia, 
based mainly upon material which the author and his colleagues have 
collected during the past ten years in South Africa, and which is now repre- 
sented in the Mycological Herbarium of the Union of South Africa at 
Pretoria. 
The material has been collected primarily with the object of elucidating 
the life-histories of the various rusts which are so destructive to many of 
our economic crops, and it is hoped that the descriptions of these parasites, 
of which this is the first instalment, may promote a more widespread interest 
in this group of plants and may be the means of adding considerably to our 
present very imperfect knowledge of these fungi. 
" Heating and Cooling Apparatus for Rontgen Crystallographic Work." 
By J. Steph. v. d. Lingen. 
The apparatus described has been devised by the author in order to 
facilitate the work of those who wish to carry on research on the determina- 
tion of the energy of an atom at zero temperature and at very high tempera- 
tures. The energy of atoms and its relation to temperature is one of the 
many problems of modern physics. Since the publication of de Bye's 
extension of Von Lane's theory of Rontgen interference, several experiments 
