T V Y vrl, etï-th
P l a t e CXXXVI.
CALLITHAMNION TLTRAGONUM, Ag.
G en . Ch a e . Frond rosy or brownish-red, filamentous; stem either opake
and cellular, or translucent and jointed; branches jointed, one-tubed,
mostly pinnate (rarely dichotomous or irregular); dissepiments hyaline.
F ru it of two kinds, on distinct plants; 1, external tetraspores, scattered
along the ultimate branchlets, or borne on little pedicels; 2,
roundish or lobed, berry-like receptacles (favelld) seated on the main
branches, and containing numerous angular spores. Callithamnion
[Lyngh.),—from kúWís, beautiful, and Bagviov, a little shrub.
Callithamnion tetragonum-, outline of the frond ovate; stem cartilaginous,
sub-simple, setaceous, somewhat opake, veiny, set with subqna-
drifarious lateral branches, furnished sometimes with a second or third
series ; penultimate branches pelluoidly jointed, slender, elongate, set
with short, alternate, patent, level-topped plumules, the lowest of which
are simply pinnate, t ie upper sub-bi-pinnate ; ramuli incurved, narrowed
at the base, suddenly acuminate, their articulations once and a
half a long as broad, constricted at the joints ; tetraspores exceedingly
minute, oval, near the tips of the ramuli.
Callithamnion tetragonum, Ag. Sp. Alg. vol. ii. p. 176. Harv. in Iloolc.
Br. M. vol. ii. p. 343. Harv. in Mack. FI. Hib. part 3. p. 315. Harv.
Man. p. 108. Wyatt, Alg. Banm. no. 90. J. Ag. Alg. Medit. p. 74.
Endl. 3rd Suppl. p. 34.
Ceeamium tetragonum, Ag. Syst. p. 137.
CoNEEETA tetragona, With. vol. v. p. 405. Billw. Conf. t. 65. E. Bot. 1 .1690.
H ab . Parasitical on the larger Algæ ; commonly on the fronds of L aminaria
digitata. Annual. Summer. Shores of England and Ireland.
Geoge. Dis t e . Atlantic shores of Europe. Baltic and Mediterranean Seas.
D e sc e . Boot scutate. Eronds from two to five inches in length, with a broadly
ovate general outline. Stems thicker than hog’s bristle, smooth, or clothed
with short hah’-like ramelli, jointed, but more or less opake from the veins
which traverse the articulations, subsimple, furnished throughout with
numerous lateral patent, alternate, suhquadrifarious, simple branches,
the lowermost of which are longest. These branches are similar to the
main stem, and bear a second or third series of lesser branches, all of which
are perfectly simple. The penultimate branches are about half an inch long,
peEucidly jointed, and clothed with very short plumules, set alternately.
Plumules not half a line iu length, the lowermost sub-simple or pinnate, the
upper gradually more compound. Bamuli incurved, robust, thickest in the
middle, suddenly acuminated at the point. Articulations of the stem and
branches from' two to three, or rarely four times as long as broad ; those of the
ramuli pretty constantly once and a half as long as their breadth. Tetraspores
very minute, oval or oblong, sometimes transversely zoned, usually
tripartite, borne near the tips of the ramuli, one or two on each ramulus.