and rounder. Cystocarps are unknown. etvaspores ave borne in the peri- 
pheric cells of little roundish wavy spore-leaves, which occur in tufts (like 
small double roses), either at the ends of the branches, or bursting irregularly 
from any part of the side. The cellular structure of the frond is very dense, 
composed of minute cellules. The colour is a dark dull brown-red, turning 
still darker in drying, and a horny brownish-white on exposure to the 
weather. The sudstance is extremely rigid and tough, harsh to the touch. 
In drying, the frond does not adhere to paper. 
This is the original species on which Kiitzing founded his 
genus Thamnoclonium. It had previously been placed, by J. 
Agardh, in the genus Polyphacum, one of the Rhodomelacee, 
to which it bears a very close external resemblance, but from 
which it differs essentially in structure, and, so far as the fructi- 
fication is known, in that respect also. None of the Rhodome- 
laceé have distinctly cruciate tetraspores, scattered through the 
peripheric stratum of leaflets, as we find them in TZamnoclonium ; 
so, whatever fate may await this genus on the discovery of its 
cystocarp, it is not likely that it will ever be again referred to 
Rhodomelacee. 
This plant is not unfrequent on the shores of Victoria and 
Tasmania, bemg cast ashore from deep water. When first 
thrown up it is very dark-coloured, but as commonly seen on 
the shore is either much paler or nearly colourless. 
Fig. 1. THAMNOCLONIUM HIRSUTUM,—the natural size, 2. Apex of a branch, 
with two terminal spore-leaf clusters. 3. Section through a ramulus. 4. 
Cellular tissue of the same. 5. Section through a spore-leaf. 6. Tetra- 
spores from the same :—variously magnified. 
