Merismopedia punctata Jenner, in Fl. of Tunbridge Wells.
Gonium tranquillum Elir., Die Infus. p. 57. t. iii. f. 3.
Hab. Ashdown Forest, Cold Bath Spring, &c.: Mr.
Jenner.
I am not at all acquainted with this pretty production ; it
doubtless, however, belongs to the family of Ulvacece, and
my Ulva binalis may possibly be identical with it.
41. T E T E A S PO R A DwA.
Char. Frond either tubular, infiated, or fla t, gelatinous.
Cells mostly arranged in fours.
Derivation. From rsrpa, four, and airopa, a seed ; in allusion
to the arrangement of the cells.
This genus seems to me to be wholly unnecessary: it ought
either to merge into Ulva, or else several species now associated
with that genus should he removed from it and placed
in Tetraspora. All the characters of the genus Tetraspora
may be found in one or other species of Ulva, and especially
that of the quaternate arrangement of the granules, or perhaps
more strictly speaking, the cells, from which the generic denomination
is derived.
1. T etraspora lubrica Ag.
Plate L X X V I I I . Fig. 10.
Char. “ Frond quite simple, tubular, suhgelatinous, waved
and serrated."
Harv. in Hook. Brit. Flor. vol. ii. p. 313.; Harvey, in
Manual, p. 176.
Hab. Hellesdon, Norfolk : Sir W. J. Hooker. Appin :
Captain Carmichael. Castlemartyr, C o rk : Miss Ball.
Malahide : Mr. Moore. Aberdeen: Dr. Dichie. In an
old quarry above Cromlyn Bog, Swansea: J. W. Gutch.
Tunbridge Wells : ilfr. Jenner.
The freshwater Ulvacece have not as yet been studied with
the attention which they require. I do not feel at all certain
that either this species, or Tet. gelatinosa are really distinct
from Ulva bullosa: at all events, it is certain that in
Ulva hullosa in its young state the frond is saccate or tubular,
and the granules arranged in fours: neither can any difference
he detected in the size of the cells In these supposed species:
all which circumstances lead to the suspicion tha t they are
but states of the same production. I f the observation of
Vaucher be correct tha t the granules or cells undergo an increase
of size at the period of the complete developement of the
frond, and ju st before it passes to decay, then it would seem
tha t no certain character can he derived from their size, unless
the condition of the species as to age be likewise ascertained.
The frond of T. lubrica is stated to he larger than in the
following species, less gelatinous, with a more distinct membrane
and of a deeper colour. The tube finally ruptures, and
becomes membranaceous, with an irregular outline.
2. Tetraspora gelatinosa Desv.
Char. Frond ovate, inflated, and very gelatinous.
Hook. Br. PI. p. 313.; Harv. in Manual, p. 176.
Hah. In freshwater streams attached to aquatic p la n ts ;
Newcross, Killarney : W. H. Harvey. Botanic Garden,
B e lfa st: Dr. Drummond. Malahide : Mr. Moore.
“ Frond exceedingly lubricous and gelatinous, but firm,
delicately waved, and plaited, of an oval outline. Sporules
bright green, or arranged in fours or scattered.”— Harv.
3. T etraspora elava Hass.
Plate L X X V I I I . Fig. 11.
Char. Frond when dried yellowish. Cells very minute.
Hah. Rocky rivulet, co. Antrim : Mr. Moore.
This species at all events would appear to be distinct, the
cells being two or three times smaller than those of the two
preceding Tetrasporce.