210 Transactions of the Royal Society of South Africa. 
out, it expands slightly owing to the development of several short, flanking 
tracheides. The next leaves in order of development are found to possess 
a more complex vascular tissue. The protoxylem of the vein is accompanied 
by two more or less interrupted groups of spiral and reticulate transfusion * 
Fig. 23. Fig. 24. 
tracheides, which may appear at any point between base and apex. All the 
upper leaves of the plant, including the sporophylls, show two well-developed 
bands of transfusion tracheides to right and left of the protoxylem (figs. 22, 
23, 24). These bands of tracheides do not accompany the leaf -trace into 
the stem. There is evidently a connection between the amount of trans- 
fusion tissue and the number of stomata on the leaf-blade. The only other 
Fig. 25. Fig. 26. 
species of Selaginella in which a similar triple mid-rib has been noted is 
S. laevigata, Bak., var. Lyallii, Spr. (5). Bruchmann in 1909 published an 
account of the vegetative organs of this species (2), but I have not had the 
opportunity of consulting his paper, nor yet of obtaining material of the 
species for comparison with S. pumila. 
The shape of the ligule was found to vary considerably, as shown in 
* The use of this term implies no expression of opinion as to the phylogeny of the 
tissue in question. 
