Ser. RuoposPERME. Fam. Rhodomelee. 
Pirate CXLVII. 
POLYSIPHONIA PARASITICA, Grev. 
Gen. Cuar. Frond filamentous, partially, or generally, articulate; joints 
longitudinally striate, composed of numerous radiating cells or tubes, 
disposed round a central cavity. ruetification two-fold, on different 
individuals; 1, ovate capsules (ceramidia), furnished with a terminal 
pore ; and containing a mass of pear-shaped spores. 2, ¢etraspores, 
imbedded in swollen branchlets. PotysrpHonta ((rev.),—from 7odds, 
many, and oper, a tube. 
PotystpHoNta parasitica; filaments slender, rigid, full-red, alternately 
branched, distichous; branches bi-tripinnate; pinnules closely set, 
erecto-patent, alternate, awl-shaped, acute ; articulations about as long 
as broad, marked with three or four broad hexagonal oblong cells (or 
siphons) separated by pellucid spaces ; siphons about eight, surrounding 
a narrow cavity; capsules ovate, on short stalks; tetraspores im- 
mersed in swollen pinnules. 
PoLysIPHONIA parasitica, Grev. Hl. Edin. p. 309. Harv. in Hook. Br. Fl. 
vol. ii. p. 330. Wyatt, Alg. Danm. no. 175. Hare. in Mack. Fl. Hib. 
part 3. p.3. Harv. Man. p. 85. Endl. 3rd Suppl. p. 46. 
Hureutnsta parasitica, 4g. Syst. p.147. Ag. Sp. Alg. vol. ii. p. 103. 
Hurcuinsta Mostingii, Lyngd.Hyd. Dan. p. 116. t. 36. 
ConFERVA parasitica, Huds. Fl. Ang. p. 604. (?) Dillw. Conf. Syn. p. 87. 
E. Bot. t. 1429. 
Has. Parasitical on the larger Algz, and, much more frequently, on various 
species of Melobesia, at the limit of low water, and in from four to 
fifteen fathoms water. Rather rare; but very generally distributed 
on the British coasts, from Orkney to Cornwall. Remarkably fine on 
the Ayrshire coast, and at Arran, ev. D. Landsborough. 
Geoer. Distr. Atlantic shores of Europe, from the Faroe Islands to Spain. 
Malta, Dr. Lyall. 
Descr. Fronds several from the same base, but not densely tufted, from one to 
three inches in height, with an undivided or once-forked stem, not quite so 
thick as hog’s bristle, fuwmnished throughout its length with closely-set, 
alternate, distichous branches. Branches very variable in length; in some 
specimens not half an inch long; in others, almost two inches, regularly 
bi- or tripinnate ; the pimme gradually diminishing in length from the base 
to the apex, closely set, erecto-patent, alternate; pinnules from half a line 
to a line in length, simple, subulate, alternate, acute. Sometimes the 
branches are nearly naked, the pinne few, and simply pinnate ; and towards 
the base of the branches, in large specimens, the lower pinne are short, 
simple, and recurved. Aréiculations of the pinne about as long as broad, 
those of the pinnules shorter, marked with several oblong tubes, which are 
pointed at both ends, and separated by hyaline spaces. A transverse section 
VOL. Il. G 
