V i POLYSIPHONIA A g a r d h u n a .
Rigid sessile-fruited Polysiphonia.
C l a s s a n d O r d e r CRYPTOGAMIA ALGÆ, L i n n S A i . O e d . ALGÆ, J uss.
GEN ERIC CHARACTER.
Frons Jiliformis (rubra), ramosa, articulata ; articuli tubulis pluribus internis
striati. Fructificatio duplex, tubercula externa aut apicibus ramuhrum innata.
Frond filiform (red), branched, articulated; articulations striated with several
internal tubes. Fructification double; external tubercles or innate
ones towards the summit of the branches.
S PE C IF IC CHARACTER.
P o l y s i p h o n ia Agardhiana ; ehngatis, ramosis, rigidiusculis, ramulis sub-
fasciculatis basi apiceque attenuatis, articulis inferioribus diametro duplo vel
tiiplo longioribus, superioribus subæqualibus; capsulis rotundato-convexis omnino
sessilibus.
P. filiform frond elongated, branched, somewhat rigid, ramuli subfaciculate,
attenuated at the base and the apex, the lower articulations twice or
thrice as long as their diameter, the upper ones nearly as long as broad ;
capsules rotundato-convex, quite sessile.
H a b . On stones in the sea. Appin, Captain C a r m i c h a e l . F rith of Forth,
only near Kinghorn, but there tolerably plentiful. Summer.
Frond 6—12 inches long, of a full red colour when growing, becoming blackish
or very dark when dried, much and irregularly branched, rather rig
id ; branches erect, variously divided, the ramuli 2-S hues in length,
attenuated at the base and apex, and mostly given off in a fasciculate
manner, especially towards the lower part of the plant. The articulations
vary somewhat in the same parts. The lower ones are from 2-3 times
longer than their diameter, sometimes, though rarely, contracted at the
joint : ai-ticulations o f the branches about as long as they are broad, with
5 evident striæ; nearer the summit they become rather shorter. In
the ramuli (many of which are considerably thickened in the middle),
the articulations are very short, but the striæ change their figure, to
accommodate the diameter of the p a r t; some of them have become in
this way oblong, many even nearly square. Capsule appearing like a
sessile tubercle, globoso-convex, fixed by a very broad base to the
branches, containing 6-10 granules, which appear to be composed of a
mass of minute, roundish, reproductive particles or seeds. In the young
state, it adheres to paper; when mature, very imperfectly.
VOL. IV.