26 
The Queensland Naturalist 
May, 1942 
sheep” because from a short distance they look for all the 
world like resting sheep. Other cushion plants look like 
rocks, while some Tasmanian ones are prickly. 
The shape of these plants help to prevent loss of water 
by transpiration, owing to the reduced transpiring area. 
Other species economise water by producing leaves which 
are very small and often hard or spine-like. In yet others 
a covering or partial covering of woolly hairs help to pre- 
vent the loss of water and sometimes even help the plant 
to absorb dew. A kind of resin coats some plants so that 
these feel quite sticky to the touch. 
One very common type of desert plant is the succu- 
lent, type, many of which have been brought into cultiva- 
tion, such as the various species of Agave , Aloe , and 
Cactaceae. The Cactaceae (or Cacti , as they are popularly 
called) are found in the deserts of Mexico and the neigh- 
bouring regions of the United States, and often grow to 
a great size. They have no ordinary leaves, these being 
represented only by sharp spines such as are seen on the 
prickly pear. The usual work of the leaves is carried on 
by the stems which are always fleshy and swollen, usually 
jointed, and quite varied in shape, some being long and 
cylindrical, others are almost globular so that the plants 
look like huge spiny pin cushions, others again are flat- 
tened from side to side as is the prickly pear, while in 
addition many are fluted from top to bottom. These Cacti , 
as do other succulents, store up large quantities of water 
in their stems, and are sometimes cut by thirsty travellers 
to obtain this water. In some of the African deserts, 
plants similar in appearance to Cacti are found, but they 
are not at all related to them, being species of Euphorbia 
and therefore allied to such plants as Poinsettia, asthma 
weed, etc. They do not have showy flowers as have many 
of the members of the Cactaceae. 
In some succulents, it is the leaves rather than the 
stem which become swollen and which become the water- 
reservoirs. The common pig-weed is an example of such 
a succulent, as well as being a reminder of the fact that 
many of the peculiar types of plants I have mentioned are 
not restricted to desert areas. The Parakeelya, common 
in the Australian deserts, belongs to this type, and has 
become famous because stock feeding on it are able to do 
without water. It has very showy Portulaca - like flowers 
