Ser. RHopOsPERME. Fam. Rhodomelea. 
Puate CCVILI. 
POLYSIPHONIA FIBRATA, Zarv. 
Gen. Cuan. Frond filamentous, partially or generally articulate ; joints 
longitudinally striate, composed of numerous radiating cells or tubes, 
disposed round a central cavity. Fructification twofold, on different 
individuals ; 1, ovate capsules (ceramidia), furnished with a termina 
pore, and containing a tuft of pear-shaped spores; 2, ¢etraspores 
imbedded in swollen branchlets. | PonystrpHonta (Grev.) — from 
mohus, many, and oupor, a tube. 
PotysrPHoNta jidrata; stems setaceous below, much attenuated upwards, 
flaccid, gelatinous, simple or alternately branched, bearing at greater 
or less distances, dichotomously divided, more or less pencilled ramuli, 
whose tips are fibrilliferous; axils patent; articulations bistriate, 
variable in length, those in the principal branches four to six times 
longer than broad ; siphons four, surrounding a minute central cavity ; 
capsules ovate, usually pedunculate. 
PotysrpHonta fibrata, Harv. in Hook. Br. Fl. vol.ii. p. 329. Harv. in Mack. 
Fl. Hib. part 3. p. 206. Harv. Man. p.93. Wyatt, Alg. Danm. no, 39. 
Kiitz. Phye. Gen. p. 426. Endl. 3rd Suppl. p. 45. 
Hurcurnsta allochroa £. fibrata, 4g. Syst. p. 154. 
ConFeRrva fibrata, Dillw. Conf. Syn. p. 84. t. G. 
Has. On rocks, muscle shells, &c., near low water mark, either in tide- 
pools or exposed places. Annual. Summer and Autumn. Frequent 
on the British coasts. 
Groar. Distr. Atlantic shores of Europe. 
Descr. Root, a mass of branched and matted fibres. Fronds very densely tufted, 
from two to six or eight inches in length, as thick as hogs’ bristle at the 
base, gradually attenuated upwards to a capillary or byssoid fineness, irre- 
gularly dichotomous or alternately branched ; branches more or less divided, 
either indefinitely decompound or bearing along their divisions lateral 
multifid ramuli, which sometimes are dense and pencilled, in other speci- 
mens more lax and simpler. Articulations visible throughout the whole 
plant ; twice as long as broad below; six or eight times as long in the 
middle of the stem ; three or four times in the upper branches ; and scarcely 
twice as long as broad in the ramuli:—marked with two wide, coloured 
tubes, separated by narrow pellucid spaces. Siphons four, containing 
coloured bags, and surrounding’a minute central cavity. Apices of the 
branches and ramuli terminating in a tuft of byssoid, dichotomous fibres. 
Ceramidia ovate, with a wide mouth, pedunculate, abundantly scattered 
over the upper branches, containing a tuft of pear-shaped spores. Tetraspores 
small, in distorted ramuli. <Antheridia oblong, obtuse, yellow, growing 
from the apical fibres and clustered round the tips of the branches. Colour, 
¥-2 
