Minutes of Proceedings. 
xxiii 
is entirely devoid of green tissue. Hence, as in the case of the Bulbine, 
the hght can reach the green tissue of the leaf only through the window, 
illuminating the leaf from within. 
It is considered that this structure is principally a contrivance for the 
protection of the green tissue against the destructive action of too severe 
sunlight. 
Postscript. — The plant named by Dr. Schonland Haiuorthia truncata 
in his paper which was read to-night is one of the six species described 
by Dr. Marloth elsewhere as window-plants." As his communication 
was received by the Secretary of the Society before the latter, the author 
withdraws his diagnosis of the species and cancels the name, in order 
to avoid a synonym. 
Ordinary Monthly Meeting. 
July 21, 1909. 
Professor R. Crawford in the Chair. 
The Minutes of the last meeting were read and confirmed. 
The President read the names of the five candidates whom the 
Council have selected as most eligible, i.e., A, L. Hall, E. T. Mellor, 
Sir Chas. Abercrombie Smith, A. L. du Toit, A. M. Wilson. — Mr. 
C. H. H. Fincham was nominated as ordinary member. 
The following communications were read : — 
Notes on the Absorption of Water by Aerial Organs of Plants," 
by Dr. Marloth. 
The author explained that he had made numerous experiments with 
various Karroo plants in order to ascertain whether they are able to 
absorb water by means of their leaves and thus to utilise the dew, which 
is of common occurrence in the Karroo every night during the winter. 
His results showed that some plants possess specially constructed hairs, 
like Mesembrianthemum barbatmn and Grassula tomentosa ; other peculiar 
stipules, like Anacampscros Telepliiastrum and Afilamentosa ; others an 
unusually modified epidermis, like Grassula decipiens, and others again 
aerial rootlets, like Cotyledon cristata. These organs absorb sufficient 
moisture to supply the requirements of the plants during a part of the 
year, thus enabling them to exist in arid regions like some parts of the 
Karroo or the desert coast-belt of Namaqualand. 
" Evaporation in a Current of Air (Part I.)," by J. R. Sutton. 
The result of previous observations upon the rate of evaporation made 
under natural conditions at Kenilworth (Kimberley) with gauges of 
various patterns suggests that the relative humidity of the air is of more 
importance than the absolute humidity in determining the loss of water 
