Ser. RHopOsPERME. Fam. Rhodomelee. 
Puate CLXVIII. 
POLYSIPHONIA FORMOSA, Sutr. 
Gen. Cuar. Frond filamentous, partially or generally articulate; joints 
longitudinally striate, composed of numerous radiating cells or tubes, 
disposed round a central cavity. Fructification two-fold, on different 
individuals ; 1, ovate capsules (ceramidia) furnished with a terminal 
pore, and containing a tuft of pear-shaped spores; 2, t¢etraspores, 
imbedded in swollen branchlets. PotystpHonta (Grev.), — from 
modus, many, and oper, a tube. 
PotysteHontia formosa ; filaments exceedingly slender and flaccid, full-red, 
much divided; branches subdichotomous, long, flexuous, more or Jess 
furnished with scattered, spreading, alternate, subulate ramuli; arti- 
culations marked with two broad tubes, those of the main branches 
many times (5-10 times) longer than broad, of the ramuli short ; 
siphons four, surrounding a minute cavity; capsules urceolate, gene- 
rally stalked ; tetraspores imbedded in the middle part of the ramuli. 
PoLysIPHONtIA formosa, Suhr. Bot. Zeit. 1831, p. 709. Harv. Man. p. 94. 
Wyatt, Alg. Danm. no. 216. 
PoLysrPHonta gracilis, Grev. MSS. 
Has. On rocks, near low-water mark. Annual. Summer. Not uncommon. 
Lerwick, Shetland, Suhr. Bute, Dr. Greville. Belfast Bay, Jr. 
Thompson. Antrim, Mr. D. Moore. Clontarf, Wiss Ball. Galway, 
Mr. M‘Calla. Malahide, W.H.H. River Dart, Mrs. Griffiths. 
Salcombe, Mrs. Wyatt. Plymouth, Rev. W.S8. Hore, and Dr. Cocks. 
Whitsand Bay, Dr. Jacob. Sidmouth, Rev. R. Cresswell. 
Geogr. Distr. Atlantic shores of Northern Europe. Baltic Sea. 
Descr. Filaments densely tufted, from six to ten inches in length, the larger 
specimens as slender as a human hair, the smaller and more delicate much 
more slender, excessively branched, in a manner between alternate and 
dichotomous; branches three or four inches long, flexuous, several times 
divided, the penultimate divisions more or less furnished with alternate, patent, 
subsimple ramuli, ultimate ramuli subulate, spreading. -Apices blunt, and 
often clothed with byssoid fibres. Articulations very variable in different parts 
of the frond ; those of the stem about twice as long as broad; of the main 
branches from eight to ten times; of the smaller branches from four to five 
times ; and of the ramuli about once and half as long as broad. Inter- 
stices pellucid. Capsules urceolate, scattered on the sides of the upper 
ramuli. etraspores forming a line in the middle of the ramuli, which 
then become fusiform. Colour a full, deep, and somewhat pinky-red, 
becoming red-brown, or very dark, in drying. Swdstance flaccid, mem- 
branous, or, when young, somewhat gelatinous, closely adhering to paper, 
and somewhat glossy when dry. 
M < 
