May, 1943 
The Queensland Naturalist 
41 
has a distinct main axis along each side of which are 
arranged numbers of smaller components, called primary 
pinnae. The primary pinnae may in their turn be similar- 
ly divided, their divisions being termed secondary pinnae. 
Very often the secondary pinnae are also pinnate, bearing 
tertiary pinnae, and so on. The divisions of the pinnae 
are termed pinnules. The fronds are described as simply 
pinnate, bipinnate, tripinnate, etc., according to the degree 
of division. 
The tree-ferns dealt with below fall into four main 
groups or genera, which may be distinguished as follows: — 
Sori forming a regular row on each side of the 
lobes, naked or covered by an indusium. 
Sori round: 
Indusium lacking or insignificant Cyathea 
Indusium thick, 2-lipped, the outer lip 
composed of a lobe of the frond Dicksonia 
Sori oblong, uncovered, forming a band near 
the margin of the pinnules Angiopteris 
Sori (spore masses) irregular, naked, covering 
the lower part of the under surface of the 
pinnules Todea 
CYATHEA (ALSOPHILA) 
Key to the Species. 
Pinnae not hairy except on main axes: 
Secondary pinnae incised almost to the 
midrib. Lateral veins pinnate, 
mostly once forked: 
Stalk of frond pale, rather fleshy, more 
or less prickly, especially towards 
the base: 
Bases of frond-stalks covered with 
soft fine scales and hairs: 
Trunk with persistent bases of 
frond-stalks attached 1. australis 
Trunk covered with large oval 
scars from fallen fronds 2. Brownii 
Bases of frond-stalks clothed with 
dark brown narrow bristly scales 
(Northern species) 3. Woollsiana 
Stalk and axes of frond dark, hard and 
very prickly 4. Leichhardtiana 
Secondary pinnae entire or incised less 
than half-way to the midrib. Lateral 
veins branched several times at the 
base (Northern species): 
