4 PROCEKDINGS OF THE 



contained no trace of floral organs or of daiimge by any animal 

 organisms. 



A discussion followed in which the following engaged : — Mr. E. 

 M. Holmes, Dr. O. Stapf, and the President; Dr. Rendle 

 replying. 



Prof. II. H. W. Pearsox, Sc.D., F.L.S., then gave a lecture 

 illustratf'd by a long series of lantern-slides, entitled — " Types of 

 the Yegi'lation of Biishmanland, Namaqualand, Damaraland, and 

 South Angola (A Preliminary Keport of the Percy Sladen 

 Memorial Expedition in South-West Africa, 1908-1909)," of 

 which the following is an abstract : — 



The floras of the regions named in the title are very distinctly 

 related, if the remarkable vegetation found on the Huilla plateau 

 in South Angola be excluded. Otherwise the differences that are 

 observed ar*^ probably to be accounted for mainlv as a result of 

 variation of (1) elevation; (2) atmospheric humidity; (3) depth 

 at which permanent supplies of underground water are available; 

 (4) geographical position, especially with regard to the composition 

 of the floras of contiguous regions. In all, the rainfall is normally 

 scanty and inconstant, and there is a prolonged drought in the 

 winter season. Near the coast, in some places up to elevations as 

 great as 2,700 feet, the total annual rainfall is never more than a 

 few millimetres and frequently fails altogether. 



The afllnities of these floras (again excepting that of the Huilla 

 plateau) are primarily with those of the South Central African 

 highlands. In South Angola many species are undoubtedly 

 derived from the Coast and Montane regions of West Tropical 

 Africa. Throughout, the vegetation is more or less extremely 

 xerophytic in character, and is marked either by a very short 

 period of duration or by the possession of those structural pecu- 

 liarities which are commonly found in dry climate perennials. 

 Of these, hairiness is, in general, not a conspicuous feature : 

 exce|)t in Lower Namaqualand, succulence is not especially 

 common. A round bushy habit is very marked throughout. The 

 root system is usually very deep ; the leaves are commonly simple 

 and of small size and with a strongly developed cuticle. 



The formations and associations indicated are predominant by 

 reason either of their great extent or of striking peculiarities of 

 the plants composing them. They are arranged in the main 

 geographically from South to North. 



The President having opened the discussion, it was continued 

 by Prof. Herdman, Dr. Henry Woodward (visitor), Dr. A. B. 

 Eendle, Mr. Bailey Saunders (visitor), and Dr. Stapf; Prof. 

 Pearson replying. 



