380 
PROCEEDINGS OF SOCIETIES. 
and in process of time the little plant reached dimensions just 
visible to the unassisted vision ; at this stage its tetraspores were 
found, but no trace was detected of either carpogonia or anthe- 
ridia. There were great difficulties in the way of referring this 
plant to any of Eeinsch’s species, many of which were indeed 
still without specific names. It had been found pretty common 
on L. articulata, collected about Howth during the spring of 
1879, and doubtless would turn up again, when perhaps its true 
fruits might be discovered, and with them a more perfect account 
laid before the club. 
Branching of the staminal hairs of Tradescantia. — • Prof. 
M’Nab drew attention to a singular case of branching hairs from 
the stamens of Tradescantia virginica. The penultimate cell 
gave off at its base abranch consisting of two cells, the aiis of 
growth of the branch being downwards and backwards. This 
form and three other hairs, each with a branch consisting of a 
single lateral cell, were all obtained from an unopened flo\ier- 
bud, from a cut flower-stem, which had been some time in water, 
and therefore under abnormal conditions. 
December, 1879. 
Cosmarium isthmochondrum, Nordst., new to Ireland, exhibited. 
— Mr. Archer showed, new to Ireland, Cosmarium isthmochon- 
drum, Nordst., from Connemara, and, similarly to Nordstedt’s 
own example, as he states, in company with Cosmarium gul 
narium. Both these are very rare species, but when met with 
sometimes occurring in quantity. As Herr Nordstedt remarks, 
these two species might possibly be confounded, but Mr. Archer 
thought, if their distinction were but once properly appreciated, 
such a mistake could not occur an a second occasion, for it 
needed only a little careful observation to see their striking and 
strong points of difference ; even with a low power, when one 
has got a good grasp of the outline of each, Mr. Archer thought 
they might be very readily discriminated. There could be no 
doubt but that Cosmarium isthmochondrum is a very good and 
distinct species. 
Barasitic Florideous alga in Plocamium coccineum, exhibited. 
— Dr. E. Perceval Wright exhibited some filaments of a Elori- 
deous alga, which he had found in the interior of the main 
portion of the frond of Plocamium coccineum. These filaments 
were of a distinctly red colour, were frequently branched, and 
apparently grew np within the cell tissue of the Plocamium. Dr. 
Wright had found them in November, 1878, and was again 
reminded of them by the appearance, in the ‘ Botanische Zei- 
tung’ for 17th January, 1879, of a paper by Eeinsch, on 
“ Entozoische Pflanzenparasiten,” in the plate accompanying 
which, fig. B, an almost identical form is figured. Unfor- 
tunately though watched from time to time, nothing had yet 
transpired to throw any additional light on their life history. 
