7 
ra 
. 
Buri: 
-—_ 
Seeds-of 
Fuci. 
FUCL. 
ies there 
It has already been stated, that in some 
scattered 
are found both seeds in tubercles, and s 
in the substance of the frond. Mr Turner was at one 
time of opinion, that the seeds in the tubercles might 
. become a disseminated through the frond ; 
but more examination with the microscope, en- 
abled him to satisfy himself that the lar granules 
differ as to shape from those which lie naked in the frond. 
He is incline: to believe, that those plants on which 
.the two modes of fructification occur on different indi- 
viduals, aré-truly dicecious, though a plant, possessing 
_each mode of fructification, may frequently arise from the 
same basis, and thus occasion eo Dr Soland- 
er, it may be remarked, first suggested that these might 
/bemale and female. {t would evidently be almost a 
-hopeless attempt, to endeavour to observe the mode of 
i tion in their native element ; and itis not im- 
probable that this may for ever remain among the ar- 
cana re nature. “ae ~ — 
. A few species have a iferous ten) » putting 
forth peltate leaves, Nal to lengthen inte batancliog 
if the plant have sufficient vigour. Mr Turner seems 
to think it probable, that, like the bulbs of allia, these 
new productions may fall off when the frond decays, 
and shoot up into independent individuals. Some spe- 
cies, that have broad terminal receptacles, have been ob- 
served occasionally to become ee nn particularly F. 
vesiculosus and serratus ; the s vegetating while in 
the receptacles, and thus producing the viviparous cha- 
racter. 
We have already seen, that what Stackhouse con- 
sidered as seeds, were probably capsules, as they 
burst asunder and discharged smaller ies. Turner 
makes the remark, that the seeds of different species 
have been observed to discharge very minute granular 
lobules ; and with that candour and diffidence which 
5 inguish the accurate observer, he confesses his 
doubts whether the small bodies, generally accounted 
seeds, may not themselves be a a It may 
be remarked, indeed, that his representation of the 
bursting of a capsule, (Hist. Fuc. t. 181.), and his 
figure of a seed pouring out its contents, (t. 61.), bear 
the greatest resemblance to each other. The seeds of 
fuci, in , must be very minute: they seem to 
abound imperceptibly in the sea, as the impalpable 
seeds of fungi, musci, and lichens, do in the air. 
In most of the tuberculiferous fuci there are visible, 
besides the seeds, and intermixed with them, nume- 
rous elliptical pellucid granules, much more minute 
than the seeds ; er also with many small jointed 
Jjibres, among which the seeds and pellucid granules lie 
imbedded. 
Duration of Fuci, and their Rapidity of Growth. 
The fuci, like land plants, reach maturity in differ- 
ent spaces of time, and endure for different periods, 
Many of the smaller and ‘more delicate are annual ; 
others of the herbaceous kind seem to be biennial, or at 
least frequently perish at the end of the second season ; 
and many continue for several seasons. Those with 
stems of woody texture endure for a considerable num- 
ber of years, in situations where they are protected 
from the violence of the waves during storms. Old 
stems of Fucus digitatus are 
not only compl invested with itic fuci, con- 
ferve, and flustre, like old trees with lichens and mos- 
ses, but with the pee and bark become split and 
rough, and loosened from the woody part of the stem. 
The well known Fucus saccharinus has been observ- 
ed to renew its frond in a very curious way, the new 
uently to be observed, ~ 
il 
from the base, and pushing before 
it the old frond after it has discharged its office, in the 
same way as the human nails are renewed. “ The 
plant,” observes Mr Turner, “ thus acquires a peren- 
nial growth, and as Tibullus beautifully says of the 
t, novus exuit annos.” It is the opinion of Mr 
Turner, that Fucus agarum (t. 75.) renews its frond 
in the same way. 
In. judging whether a fucus belongs to the class 
of annuals or perennials, besides attending to the ge- 
neral structure and habit, Lamouroux has pointed out 
another mark :: he has very commonly found, that those 
fuci, which bear their fructification on the branch- 
es, are perennial, while those which have it on the 
tips of the fronds are annual. 
owth proceedi 
Fuci. 
It is remarked by Mr Turner, that the smaller and Rapidity o* 
more delicate sea-weeds produce their fruit in the be- growth. 
ginning of autumn; while the larger and coarser species 
ae ge for this purpose the ‘ stormy months of winter.” 
ut the rapidity of growth of some of the large coria- 
ceous kinds throughout the winter, is wonderful, and it 
is believed has only of late been fully ascertained. The 
facts shall therefore be stated. with some minuteness of 
detail. They were observed in the course of the very 
arduous undertaking of erecting a stone-beacon on a 
low rock called the Carr, situated near the entrance of 
the Frith of Forth: and when we mention as the ob- 
server the distinguished civil engineer Mr Stevenson, 2 
man accustomed to habits of accurate observation, it is 
erhaps superfluous to add, that particular attention was 
| et at the request of the writer of this article, and 
specimens of the fuci transmitted to him. The Carr 
Rock is about 20 feet broad, and 60 feet long: it is only 
uncovered at the lowest ebb of spring tides. It was com- 
pletely clothed with the larger fuci, particularly Fu- 
cus esculentus and F. digitatus. In the course of autumn 
1813, the workmen had succeeded in clearing out and 
levelling with the pick and axe a considerable part of 
the foundation of the intended beacon, when, in the be- 
ginning of November, the operations were necessarily 
abandoned for the winter. At this time the rock was 
reduced to a bare state. The coating of sea-weed had 
at first been cut away by the workmen; the roots .o 
bases were afterwards trampled by their feet ; ad 
much of the surface of the rock had been chiselled. 
Upon returning to the Carr in May 1814, in order to 
recommence operations, it was matter of no slight sur- 
prise to find the surface again as completely invested 
with large sea-weeds as ever it was, although little 
more than six months had elapsed since the work had 
been left off, when, as already said, the rock was 
cleared of weed. In particular it was observed, that 
many newly produced specimens of Fucus esculentus 
measured six feet in length, and were already furnish- 
ed with the small appendages near the base, or pinne, 
which at maturity contain the seeds of the plant. Light- 
foot mentions four feet as the ordinary length of this 
fucus, but adds that it sometimes reaches nine feet. 
Those at the Carr Rock, therefore, were nearly full 
sized. The common tangle, F. digitatus, was general- 
ly only about two feet long ; but this species when ful- 
ly grown seldom exceeds three or four feet. It is to be 
observed, that the specimens here alluded to were ta- 
ken from that part of the surface of the rock which 
had been dressed off with the pick and chisel the pre- 
ceding autumn, they had therefore grown from the 
seed ; and indeed it was remarked, in general, that the 
sea-weeds had grown more luxuriantly on the newly- 
dressed rock, which is sandstone, than from the old 
stools, which had been merely cut over, or trodden 
