126 
PROCEEDINGS OF SOCIETIES. 
sportive character of the algae has led to much dispute—some botanists insisting 
that certain species of other authors are merely varieties. Doubts of this 
description will be more surely cleared up by the observations of many observers ; 
and it must also be borne in mind by botanists who are not very familiar with 
algae, that many of them put on such variable appearances, according to the season, 
as to lead to the belief that a summer specimen and a winter specimen of the same 
plant must be perfectly distinct species. Whilst speaking of the abundance or 
scarcity of some plants at the usual season of their appearance, I will read an 
extract from a letter I recently received from Dr. Cocks, which I regard as most 
interesting, and I look upon it as a very remarkable fact in algology. He says— 
“ I have now had eleven years’ experience in collecting, and have gained a certain 
amount of practical information, which, I confess, I had heretofore not sufficiently 
attended to. Observation and experience have taught me that there is not the 
same regularity in the time of appearance of the marine algae as there is in plants 
growing on terra firma, and that the terms annual, biennial, and perennial, are not 
applicable to the former; and that their growth and time of appearance are 
governed by laws, or influenced by causes which the algologist, even of the present 
day, is unable to explain. It is quite true that, in certain localities where I had been 
in the habit of gathering certain species for two, three, and more years successively, 
when I have afterwards wanted to obtain more they had disappeared, and, in some 
instances, have never since been found. In other instances, some plants, which 
were previously considered to be extremely rare and scarce, only picked up at 
intervals, far and few between, have suddenly appeared in the greatest profusion. 
Dr. Budd told me that two years ago, having found out where it grew, he could 
have dredged thousands of specimens of Stenogramme interrupta. Last year I 
could myself have dredged a like quantity of Sporochnus pedunculatus and 
Haliseris polypodioides, neither of which species I ever took before to say plentifully. 
A few years ago the mud bank at Cremil Passage was strewed over at low water 
with quantities of Sphserococcus coronopifolius, since when I have only taken two 
specimens. You will, of course, remember when we gathered such a quantity of 
Dasya arbuscula at Firestone Bay. I have carefully hunted over the same ground every 
year since, and have never seen a single plant; even the very commonest plants 
sometimes disappear for two, three, or more years—such as Delesseria hypoglossum, 
D. ruscifolia, Nitophyllum punctatum, &c.” Such is the experience of Dr. Cocks. 
It would be very desirable for other algologists to note the appearance and disap¬ 
pearance of plants from a locality, and then to endeavour to trace out the cause. 
With the view of promoting the object of this paper—viz., the preparation of a list 
of all recorded algae found on the shores between Balbriggan and Wicklow Head— 
I suggest that other collectors will look over their collections and give our secretary 
lists of their gatherings on those shores, that we may have as large a catalogue as 
possible of the marine botany of the district. I hope soon to increase the list, 
which, for the present, is confined entirely to Mrs. Dav_y’s collection; and before 
concluding I would beg to draw the attention of the members to the very beautiful 
and natural appearance of the specimens which were prepared after the method 
laid down in the “ Seaweed Collector’s Guide,” by Dr. Cocks, of Devonport. 
LIST OF MARINE ALGiE COLLECTED AT SKERRIES, NEAR THE NORTHERN LIMIT OF 
THE PROPOSED DUBLIN DISTRICT, IN THE SUMMER OF 1854. 
Order. 
Fucacese. 
Sporochnacese. 
11 
ii 
Laminaria ceas. 
ji 
ii 
Dictyotacese. 
ii 
ii 
MELANASPERMEJE. 
Cystoseira ericoides. 
Desmarestia ligulata. 
„ aculeata. 
„ viridis. 
Laminaria digitata. 
,, saccharina. 
Chorda filum. 
Taonia atomaria. 
Dictyota dichotoma. 
Stilophora Lyngbyaei. 
Order. 
Dictyotacem 
Chordariacese. 
ii 
ii 
ii 
ii 
Ectocarpacese. 
Dictyosiphon foenicu- 
laceus. 
Chordaria flagellifor- 
mis. 
Mesogloia virescens. 
Leathesia tuberifor- 
mis. 
Elachista fucicola. 
,, scutulata. 
Cladostephus verticil- 
latus. 
