396 Transactions of the Boyal Society of South Africa. 
work on the Cape Flora''' he gives, however, some prorainence to the 
absorption of water by special trichomes of certain succulents. Some 
cursory experiments, which I have conducted from time to time, do not bear 
out his views in this matter. f That many succulents may take up water 
through their aerial organs under special conditions arranged for them 
need not surprise us, for we have the old experiment by Wiesner that 
Seclum Faharia can do so, but there is always to be remembered that 
such experiments have very little interest, unless they show us that the 
plant under natural conditions can replace more or less by its aerial 
organs the amount of water lost by transpiration. The experiments which 
I am going to describe were conducted to throw some fresh light on this 
question. While they cannot be regarded as the last word, even with 
reference to the limited number of plants experimented with, the answer 
they give is sufficiently plain to merit consideration. 
I experimented with cut branches taken in each species from the same 
plants. These have the advantage that, when selected with reasonable 
care, they are in the same condition as regards water-contents. The cut 
stem can easily be sealed and the whole branches can easily be weighed 
on an ordinary chemical balance. They were taken from pot-plants which 
had been regularly watered when required. Except in cases which will 
be specially mentioned the cut end of each branch was at once carefully 
sealed with plasticine, to which a small quantity of vaseline had been 
added. Some of the branches were exposed on a table in the Botanical 
Laboratory of the Ehodes University College where the sun shone on 
them for several hours every day, others were exposed in the open, where 
the sun shone on them also for several hours, and where dew could be 
deposited on them. The position in the open was somewhat sheltered 
from strong westerly winds, which blew on several days. Temperature- 
readings were taken occasionally, but as these could not be taken with 
sufficient regularity day and night, they are here omitted. It may suffice 
to state that the laboratory temperature ranged from 14-19° C. in daytime. 
From the 15th to the 23rd of May the weather was rather warm for the 
time of year, while it was much cooler during the following week and 
warm again the third week. Altogether transpiration was necessarily 
much smaller than in the height of summer, while absorption of water, if 
taking place at all, would probably not be greatly affected by differences 
in temperature. There was a heavy dew every night, but only a slight 
rain fell in one night for a couple of hours, while branches were exposed 
in the open. 
* E. Marloth, "Das Kapland, insonderheit das Eeich der Kapflora, das Waldgebiet 
und die Karroo, pflanzengeographisch dargestellt," June, 1908. 
t S. Schonland, " Morphological and biological observations on the genus Ana- 
campseros, L." Report S.A.A.A.S., 1903, p. 298. 
