densely covered, at least in the lower part, with wart-like papille, which 
occasionally lengthen into ramuli. Branches (or secondary fronds) spring 
irregularly from the sides and ends of the divisions of the primary stem, 
and spread in all directions; they are excessively divided, in a trichotomous 
or polychotomous manner, the minor divisions being repeatedly whorled, all 
parts being constricted at regular intervals into spurious joints. These 
joints, in the lower part, are often half an inch long, or more, and about a 
line in diameter; in the upper part gradually shorter, and the terminal ones 
are not a line in length. All the ramuli are moniliform, with oblong or 
oval internodes. Cystocarps have not been observed. Zonate te¢raspores 
occur commonly in the internodes of the ramuli, dotting over the surface, and 
vertically immersed in the peripheric cells. The colour is a deep, full red, 
becoming darker and brownish in drying. The cross section of a young 
branch shows a thick, peripheric stratum, formed of many rows of small 
cells, a very laxly fibrous intermediate stratum, and a dense medullary 
bundle of filaments, none of which is remarkably larger than the rest; a 
section of an old branch has essentially the same structure, but the longitu- 
dinal fibres are much more numerous and densely crowded, so that the frond 
becomes nearly solid. Sudstance soft and juicy, but not gelatinous. In 
drying, the frond adheres closely to paper. 
RRA ARAL A DA ODD 
I have already said, under Plate CCXCVIII., that I formerly 
confounded the present plant with the much rarer Lrythroclo- 
nium Muellert. Besides the difference in cellular structure, illus- 
trated in the Plates, the Riabdonia is generally distinguishable 
by its thick, warted stem, rather brighter colour, more Juicy na- 
ture, and denser, more ramulous branching. It is also much 
more common, and extends over a wide district of coast. The 
first specimens I received were collected by Dr. Curdie at the 
mouth of the Glenelg; they are comparatively dwarf, compared 
with the magnificent ones which may be collected in the mouth 
of the Tamar, Tasmania, and which are large enough to cover a 
folio page ; but I find no structural difference between the larger 
and smaller. In Aadit there is a striking resemblance to the 
Chylocladia articulata of Kurope, but structure and fruit are dif- 
ferent. 
Fig. 1. RHABDONIA VERTICILLATA,— the natural size. 2. Branchlets. 3. One 
of the internodes, with ¢eéraspores. 4. Tetraspores. 5. Cross section of 
a younger branch. 6. Cross section of an older branch :—magnified. 
