. i
O k d k k X I .— u l v a c e æ .
Plants fomid in the sea, in fre sh water, or on damp ground, § c .;
o f an herbaceous green or fine purple colour, o f a thin tender
membranaceous substance, and reticulated structure, rarely gelatinous.
Frond, with a very minutely scutate root, expanded,
or tubular and continuous. Fructification, roundish and mostly
(piaternate granules, or minute spomlar grains imbedded in the
delicate membrane o f the frond.
(ÍESUS XLVII. PORPHYRA, Ag. Tab. XVHI.
(lEN. C h a r . Frond plane, exceedingly tliin, and of a purple
colour. Fructification; 1. scattered sori of oval seeds;
2. roiindisli granules mostly arranged in a quatcrnatc
manner, and covering the whole frond.
O b s . This genus, remai'kable among the U lv a c eæ for the colour
of all the known species, was separated from Ulva, by Prof. Agardh,
in his “ Systema Algarum.” The name he has bestowed upon it is
derived from the Greek term for a pui-ple colour. Besides the pecu-
iarity of hue, the twofold fructification entitle these plants to the distinction
the author above mentioned has conferred upon them. When
carefully dried, the surface is delightfully smooth and glossy, and they
form beautiful specimens for the herbarium.
1. P o r p h y r a l a c in ia t a .
Fronds aggiegated deeply cleft the segments dilated variously cut
and waved.
Porphyra laciniata, A g . S y s t. A lg . p . 190.
Ulva laciniata, L ig h t f . in F i. S c o t. p . ,974. t. 33. Ag. S p . A lg . v . 1. p . 404.
Viva umbilicalis, Sm . E n g . B o t. t . 2286. L y n g b . H y d r o p h . D a n . p . 28. a c c o r d in g t o a
s p e c im e n c o m m u n i c a te d to A g a rd h . S p r e n g . S p . P I . v . 4. p. , m
H a b . On rocks and stones in the sea. Annual. Spring to autumn.
.Lbimdant on most parts of the British coast.
Root a very minute disk. Fronds aggregated; three to eight inches
in length, narrow at the base, but immediately dilated, deeply and irregularly
cleft, cut, and waved. Sometimes the attachment is within
the margin of the frond, or more or less central, and then forms the
vAriety umbilicata of Agai'dh. Fructification; 1. roundish granules
arranged in fours, and covering the whole frond in the delicate membrane
of which they are imbedded ; 2. sori of smaller ovate granules
scattered without order chiefly towards the margin of llie frond.
Substance very tender, delicately thin and membranous. Colour red-
disli purple, in age becoming tinged with green. When dried, the
frond is firmer, moi e transparent, and a finer purple.
This and the following species are well known in most parts of
England under the name of Laver, in Scotland under that of Slolce,
and with some people are a favjiurite article for the table. They require,
however, to be stewed for several hours, in order to make them
sufficiently tender. Lightfoot mentions, that the “ inhabitants of the
Western Isles gather it in the month of March, and after pounding
and stewing it with a little water, eat it with pepper, vinegar, and
butter. Others stew it with leeks or onions. In England, it is generally
pickled with salt, and preserved in jars; and when brought to
table, is stewed, and eaten with oil and lemon-juice.”
The quaternate granules in this species are much larger than in the
following one. They are of a purple colour, and, in fact, give the colour
to the frond; for, by removing the granules, which may be done
with care, under the microscope, the membrane is left perfectly colourless
and diaphanous.
, 2. P o r p h y r a v u l g a r is .
Frond ovate-lanceolate, the margin more or less waved.
Porphyra vulgaris, Ag . A u f z ä h lu n g in d e n o s tr e ic h is c h e n L a n d e r n , p . 18.
Porphyra purpurea, Ag. S y s t . A lg . p . 191.
Viva purpurea, R o th . C a t. B o t. v . 1. p . 209. t. 6. L y n g b . H y d r o p h . D a n . p . 29. Ag.
S p . A lg .-v . 1. p . 405.
Viva umbilicalis, v a r . elongata, G r e v . F I. E d in . p . 29ik
Viva umbilicalis, L ig h t f . F I . S c o t. p . 967. in p a r t .
H a b . On rocks and stones in the sea. Annual. Spring to autumn.
Coast of Devonshire. Near Belfast, Dr Drummond. Very common
on the coast of Scotland.