Fucus Mackaii was discovered in the year 1805, on the western
coast of Ireland, by Mr. James Townsend Mackay, author of the
Flora FLihernica, in honoiu- of whom the species has been
named by Mr. Dawson Turner in his great work, the ‘ Historia
Fucorum’. For a long time the frnctification remained undiscovered,
and, consequently, a doubt rested on the validity of the
species, the resemblance, in many respects, to a dwarfed variety
of Fucus nodosus suggesting a probability that it was only a form
of that plant. No doubt the connection between these plants is
very strong, yet the difference in ramification is so great, and the
constancy of character observed in Fucus Mackaii in many wMely
distant localities in which it has been abundantly found, is so
remarkable, that added now to distinctions, afforded by the position
of the fruit, its characters are better established. Still, its
habitat is anomalous, and it may he urged that the peculiar
characters originate in this habitat. The Fuci in general axe attached
by scutate roots to rocks and stones; Fucus Mackaii invariably
lies unattached, resting in its place, by its own weight,
on mud, gravel, or among loose boulders. In such situations it
flourishes from year to year, and fruits abundantly.
The fruit was first observed by Dr. Greville in the autumn of
1842, .in the collection of Mrs. Captain Maynard at Stanraer, to
whom it was communicated by Dr. Lindsay from the Isle of Skye.
More recently, in the Spring of 1846, Mr. Me’ Calla found an
abundance of specimens in fructification, which is, probably,
produced every year, but from the early season at which it is
formed, when few botanists have an opportunity of seeing the
plant, unless resident near its place of growth, the fruit has
hitherto escaped detection. From a fine specimen, communicated
to me by Mr. Me’ Calla, in a fresh state, my figure has been
taken, and I have since (in June) had the pleasure of gathering
fine fruiting specimens in the Sound of Skye. The pendulous
receptacles, produced at the bases of the main branches, and
the contrast between their clear greenish yellow, and the ohva-
ceous colour of the frond, have a very pretty effect.
Fio- 1 F u cu s M a c k a i i 2. Transverse segment o f a receptacle.
s’. A spore. 4. portion of the net-work from the centre of the receptacle:
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