Vascular Anatomy of Platycerium. 311 
ON THE VASCULAR ANATOMY OF THE RHIZOME 
OF PLATYCERIUM . 
By Harriet E. Allison, B.Sc., 
Carnegie Research Scholar, Glasgow University. 
[With Five Figures in the Text]. 
HEN this investigation of Platycerium was begun, it was 
not anticipated that the vascular anatomy would show 
such complexity of structure as now appears. The axis of the 
fern is much abbreviated, and the stelar structure much divided, 
forming an anastomosing network. The leaves, which are of two 
kinds, are so closely arranged on the axis that before one leaf- 
trace is clear of the axial system, another is being given off from 
it. Moveover, it was found that a medullary system was present 
in the more complex cases. I have worked through several species 
of the genus, both in the old and young condition. But though 
the results may have their value ultimately as helping to define 
the position of Platycerium among the Ferns, they do not supply 
any readily appreciated or immediately distinctive points. I shall, 
however, attempt at the close to indicate along what lines the 
relationships of Platycerium may be found. 
Platycerium alcicorne Desv. is one of the smaller forms of the 
genus. The rhizome is dorsiventral, with leaves inserted on the 
upper surface, and the lower surface covered with dark wiry 
rootlets. The leaves, which are of two kinds, the nest-leaves and 
Fig. 1 .—Platycerium alcicorne. Side view of rhizome: a , foliage-leaves; 
b, nest-leaves ; c, vegetative bud. 
