The subject of the present plate, though in some degree known
to Linnaeus, who confounded it with Thcus disticJms, was first
clearly described by Desfontaines in 1798, under the name oiFucus
polypodioides; and in 1801 figured by Mr. Stackhouse in the first
number of his “ Nereis Britannica,” under that of Fucus membranaceus.
The former appellation, which alludes to the resemblance
wliich its fructification bears to that of a Polypodium has been
generally adopted. As may be seen by the number of stations on
record, this plant is widely distributed over the warm parts of the
world. In the British Islands it is decidedly rare, and chiefiy found
on the southern and western shores. It does not appear to be found
in Scotland. In the south of Europe it is common, especially in
the Mediterranean, and has been brought from the tropics of
either hemisphere. I have not seen Cape specimens, but Ecklon
is reported to have gathered it in AJgoa Bay.
Mrs. Griffiths, who first discovered the scattered spores, finds
occasionally specimens in which the frond is marked, in the place
usually occupied by the sori, with brown, wavy, map-like lines
enclosing spaces which are usually more transparent than the rest
of the frond. They probably indicate a diseased state of the fruit-
producing cells.
Several other species of Haliseris are now known, aU natives
of warm latitudes, and all with much the same habit. Some have
thick, almost coriaceous fronds; and others are much more tender
and delicate than the European species; some have serrated, and
others crisped margins ; but the mode of branching is similar in
all.
Kg. 1. H a l is e r is p o l y p o d io id e s , with sori. 2. A segment, with scattered
spores :— natural size. 3. Portion of a frond wnth scattered spores. 4. Portion
of a frond with a sorus. 5. Spores from the sorus :— all more or less
higlily magnijied.
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