il a'
late form, and are composed of dicbotomously branched, jointed, obtuse,
crowded filaments, radiating at a right angle from a longitudinal
axis running through the whole ramulus, the surface of which is
formed by tbe naked apices of the filaments. A pink line marks the
axis, and in the widest part swells into an elliptical dark mass, apparently
the immediate seat of the fructification ; but whether seeds or
capsules actually exist there, I have not been able to satisfy myself,
still less their form or nature. Substance tender and somewhat gelatinous.
Colour a lively rose-pink. In drying it becomes darker and
less brilliant, shrinks considerably, and adheres closely to paper.
From its delicate nature, this elegant sea-weed is extremely liable
to injury, and most of the specimens that the botanist is fortunate
enough to find are generally mutilated. When deprived of its ramuli,
and battered by the waves, it has a close resemblance to Ceramium
rubrum. It occurs extremely rai'ely on the coast of Normandy,
from whence a specimen has been kindly presented to me by M.
Chauvin.
G e n u s X L II. P T ILO TA , Ag. Tab. XVI.
Ge n . Ch a r . Frond compressed or flat, pectinato-pinnate, o f
a red colour, between membranaceous .and cartilaginous.
Fructification minute, aggregated; capsules surrounded
by an involucre.
Obs . This is one of the most beautiful, as well as the most natural
genera of marine Alga;. The four species of which it is composed
are elegantly pinnated and feathered with numerous and regular
branches, whence the name appropriated by Agardh. By Lamouroux
it was included in his ill-defined genus Plocamium ; he was probably,
however, unacquainted with any of the species subsequently discovered,
or he could not have failed to have been struck with the singularly
natural characters exhibited by the fructification, as well as the
habit, of the individuals—characters that impressed the excellent
Turner at once with the conviction that they would at some future
time be associated.
1. P t ilo t a pl um o sa . Tab. XVI.
Frond compressed filiform branched, branches several times closely
pinnated, the pinnæ opposite, fructification terminating the ultimate
pinnulæ.
Ptilota plumosa, Ag . S p . A lg . v . 1. p . 385. S y s t. A lg . p . 195. L y n g b . H y d r o p h . D a n .
p . 38. G r e v . F I . E d in . p . 297* S p r e n g . S p . P I . v . 4 . p . 344.
Plocamium plumosum, L am o u r . E s s a i, p . 50.
Fucus plumosus, L in n . S y s t. N a t . v . 2. p . 718. H u d s . F I . A n g l. p . 587- T u r n . S y n . F u c .
p . 296. H is t. F u c . t . 60. Sm . E n g . B o t. t . 1308.
V a r . / 3 capillaris, f r o n d fla c c id , v e r y n a r r o w , t h e p in n æ j o in t e d , n e a r ly c y lin d r ic a l.
Fucus plumosus, v a r . capillaris, T u m . H i s t . F u c . t . 60. f . g—k .
Ptilota plumosa, v a r . tenuissima, A g . S p . A lg . v . 1 . p . 386. S y s t . A lg . p . 195.
H a b . In the sea. Perennial. Summer and autumn. Var. a frequent,
especiallyin Scotland, almost always growing upon the stems
o( Laminaria digitata. Var. ^ always growing on the perpendicular
sides of rocks. Not uncommon on the southern shores of England,
Turner. At Torquay and Peakhead rocks, near Sidmouth. Lossiemouth,
in the north of Scotland, Mr Brodie. Staffa. Isle of Bute.
Frith of Forth.
Root a small disk. Fronds compressed, mostly somewhat tufted,
three, to twelve inches or more in'length, irregularly branched; the
main stem and branches from half a line to a line in width, attenuated
towards the extremity ; branches commencing near the base, few or
numerous, simple or subdivided, distichous, varying greatly in length,
the lower ones sometimes only a little shorter than the entire plant, all
of them closely set with distichous horizontal pinnæ half a line or a
line apart ; these pinnæ are opposite, and vary so much in different
specimens, that, while the width of the branches, including the pinnæ,
in some cases is less than half an inch, in others it is two inches. The
pinnæ are also set with two or three series of pinnulæ, each smaller
and finer than the preceding one, and given off at shorter intervals.
The general outline of the termination of the branches is elliptical.
Fructification, two or three minute spherical capsules, with a pellucid
border, surrounded by an involucre, and terminating some of the ultimate
pinnulæ. Involucre composed of several linear incurved segments.
Capsules containing three or four roundish seeds. Besides
this kind of fructification, there is another which is sometimes found
on distinct individuals, consisting simply of roundish seeds or granules,
having a pellucid limbus, solitary or several clustered together, and