B O T 
to conceive in what manner the mode of propagation could 
fucceed, according to Gaertner’s theory ; for, as the con¬ 
fervas are frequently of an equal fize with thofe branches 
which fuppoft them, it is by no means probable, that the 
jointed globule of a conferva (if this be the author’s mean¬ 
ing) could fo inltantaneoufly attach itfelf to fuch a body, 
and with tenacity fofficient to re lift the conftant collilion of 
tides. That the globules confift of the medullary fub¬ 
ftance of the plant ilfelf is readily admitted ; at the fame 
time, it mull be allowed, that all the confervas, which 
produce the granulated veflels or feeds imbedded in thofe 
globules, bear a ftriking refemblance, in their mode of pro¬ 
pagation, to the more perfect fucufes ; and not being ap¬ 
parently fubjeft to the laws of florefcence, attain their (late 
of fructification in a manner exadtly (imilar. to that, which 
has been afcribed to the latter; from an inherent felf-effi- 
cient principle, equivalent indeed, though entirely different 
to that, on which the fexual diftinction is founded.” 
The generic character, and fubdivifions of the Fucus, 
alfomecfby Profeftbr Martyn, and Dr. Withering, areas 
follow : Fr unification, confiding of capfule-like globules, 
or of granulations within the fubftance of the plant, with 
a perforation above them. Male; Velicles fmooth, hol¬ 
low, with villofe hairs within, interwoven. Female: Ve- 
fcles fmooth, filled with jelly, fprinkled with immerfed 
grains prominent at the tip. Seeds, folitary. The effential 
character, though confelfedly imperfeft, cannot, in the pre- 
fent (late of things, be fully afcertained. The fubdivifions 
by Dr. Withering are as follow : i. Fucus with bladders 
in the fubftance of the leaf. 2. With the leaves pod-like. 
3. With the branches of the frond jointed, like a necklace. 
4. With the frond flat, midribbed, opake, or elfe pellucid. 
5. The frond flat, but riblefs ; opake, or elfe pellucid. 
6. Branches of the frond cylindrical ; and either opake, 
or pellucid. 7. Frond capillary, divided alfo into opake, 
and pellucid. 
Examples for Investigation. 
The fubjefts we (hall now delineate, are taken from 
Major Velley’s recent publication ; the firft of which is 
the Fucus veficulofus, or fea oak ; being one of thofe con¬ 
taining bladders. This fucus commences its vegetation by 
a frond or Angle leaf, and grows upon the furfaces of rocks 
and (hells. Its bafe appears like a thin glutinous fubftance, 
ftrongly adhelive to the body on which it is fixed. In the 
further ftages of its growth, the foliaceous part is frequent¬ 
ly worn away by the force of the forge, and the middle 
rib or nerve" acquires all the .appearance of a folid ftem, 
being entirely bare and nearly cylindrical, for the fpace of 
half a foot or more above the bafe. The frond in the 
mean time continues increafing in a dichotomous mode of 
growth, to a confiderable extent, furniftied with nume¬ 
rous branches. It has alfo air-bladders for the purpofe of 
buoyancy ; and at length terminates with diftended !um- 
mits, containing a tough gelatinous mafs, around which a 
number of callous globular tubercles are fixed to the inte¬ 
rior fide, (as reprelented in fig. 18 ;) each of which is fur¬ 
niftied with many feeds. When the plant arrives at matu¬ 
rity, the mafs becomes mucilaginous, and by the help of 
glades appears to be enveloped with fine capillary veflels, 
irregularly reticulated. At this period, feveral fmall 
punctures or perforations are frequently vifibleon the fur- 
face of the fummit, and the tubercles now have a more 
prominent appearance. This latter circumftance is in 
fome meafure owfing to the dilfolved date of the gelatinous 
fubftance. Each pundfture is fobtended by the upper part 
of its refpedtive tubercle, and is no doubt the channel, 
through which the fources of propagation are difperfed. 
A fpecimen of this fucus in its laft ftage of maturity and 
approaching to decay, being examined, the capillary vef- 
fels in the fummit were found to be afperfed with a fub- 
flance not unlike the farina of a plant. In order to difco- 
ver the caufe of this appearance, a fingle tubercle detached 
from the fummit, was placed under the microfcope, and 
eautioufly prefled with a fine inftrument; when one of the 
ANY. 2 S 7 
minute grains contained within it was feen to explode, and 
with an elaftic force feemed to difchargea pulverized fub¬ 
ftance, fomewhat fimilar to the particles which proceed 
from a lycoperdon or truffle. The extreme minutenefs of 
the objedt defeated all attempts to profecute the experi¬ 
ment. And we are not authorized upon an accidental ap¬ 
pearance to aftert that the particles in queftion were ana¬ 
logous to feeds ; fince they might pollibly be afcribed to 
the decayed and putrefcent (late of thofe granulated bo¬ 
dies. And yet, in favour of the former opinion, it may 
not appear improper to obferve, that the powder proceed¬ 
ing from tlie Lycoperfton bovifta, and which exceeds all 
calculation, is, according to the late ingenious Mr. Light- 
foot, confidered as the feeds of that plant. If then thefe 
minute grains, which in fome fpecies of marine plants are 
but few in number, (liould prove at laft not to be the ac¬ 
tual feeds, but only pericarpiums containing the feminal 
atoms ; we may be enabled more readily to account for 
the promif'cuous growth of thofe plants on the fined edges 
of each other, as well as on the fmootheft furfaces of hard 
extraneous bodies. The central nerve feems indued with 
an adtive vital principle, from whence, upon any fradture, 
new leaves Ihoot forth. There are feveral varieties of this 
fpecies. One of them is reprelented in the plate, to which 
the Conferva fucicola is attached. They have been con¬ 
fidered by fome as diftindt fpecies, but Gmelin very pro¬ 
perly brings them back to one fpecific character. 
Fig. 18, part of the frond of the fucus veficulofus, blad¬ 
der fucus, or fea oak, with diftended fummits, in its na¬ 
tural fize. Fig. 19, the apex magnified, to fliew the per¬ 
foration through which the feeds are difperfed. Fig. 20, 
a tubercle in its natural fize, and fcarcely larger than a 
grain of muftard ; with a figure of the fame as it appears 
when highly magnified. Fig. 21, part of the tubercle, 
containing the feeds or grains. Fig. 22, a fmall part of 
the frond magnified, to (hew the fine capillary veflels or 
hairs, which Reaumur confidered as the mule flowers; and 
on which the above male charaEler was alfumed. Fig. 23, 
a fmall part of the frond of another plant, to (hew the Con¬ 
ferva fucicola , marked a, attached to it. Fig. 26, Plate X. 
illuftrates the fucus coccineus, or fcarlet fucus, a fpecies of 
the capillary pellucid kind; with fructifications black and 
globular. 
The Confervas, or river-weed, are all inhabitants of the 
water, fome in frefh, but mod in fait water. Their fpe¬ 
cific character is as follows : filaments mod Ample, capiT- 
lary, jointed very Ihort, crowded together, containing glo¬ 
bular granules. Fig. 24, reprefents a very minute conferva, 
the fame as on the focus, fig. 23 ; but it does not feem to 
poflefs that indifference with refpedt to the place of its 
growth which marine plants generally do. The filaments 
are tubulous, and have numerous diaphragms ; their ter¬ 
mination is obtufe. When viewed feparately they are al- 
moft tranfparent, or have a light yellow tint; but in the 
mafs their colour is deeper, and partakes of a muddy yel¬ 
low or brown. It is found in great abundance under an 
elevated cliff near Weymouth, called the Look-out; parti¬ 
cularly in the fpring months. The fructification of this 
Ipecies has not yet been difeovered. A very lingular in- 
ftance of irritability has been obferved by Major Veliev in 
the Conferva corallina, iigon its being immerfed, in a re¬ 
cent (late, in frefti water. After it had been in the water 
a few minutes, feveral fibres were obferved to move in an 
horizontal direftion with a quick convullive twitch, and 
then to flop fuddenly : this they continued to do for fome 
length of time ; and the fame effedt may be produced fe¬ 
veral times, provided the plant be frefti. It is remarka¬ 
ble that this experiment does not fucceed in fait water.—» 
See the articles Fucus, and Conferva. 
All the fea-weeds are valuable as manure, and are ufed 
to great advantage by the farmers on the coaft. Others 
burn them to make kelp, by which they conftitute a valu¬ 
able article of commerce. Many fpecies make beautiful 
fpecimens for the herbarium ; and are often feen difpofed 
on paper fo as to form a fort of pidUrre. The more tender 
x plants- 
