Fig. 30. Ephedra alata. A, Transverse section of bark 
of a young branch. B, T. S. of a year-old branch. X 230. 
The anatomical structure of the green bark is briefly 
described by Vorkens (p. 151), and Ross (p. 17) describes 
an undetermined Ephedra species. Fig. 30 shows the 
assimilating cortex of a young and of a somewhat older branch. 
The outer wall is very thick with a strong cuticularised 
layer. The palisade cells become more rounded towards the 
interior and at the same time contain less chorophyll. Below 
the epidermis and in the deeper layers there are numerous 
sclerenchyma-cells which traverse the stem longitudinally; 
in the older branch their lumen has almost disappeared. 
Ammodendron Conollyi Bge. (The Sand-Acacia). 
This species is found in the sand-desert and prefers 
deep sand. It attains a height of 2—4 (—8) metres and is 
a shrub (on the more stationary soils) or more frequently a 
slender and in most cases a one-stemmed tree. The hairiness 
of the leaves gives it a whitish grey appearance, the crown 
