Ser. RHODOSPERME. Fam. Ceramiee. 
Puate CCXCVI. 
CALLITHAMNION PLUMA, «%. 
Gun. Cuar. Frond rosy or brownish-red, filamentous ; stem either opake 
and cellular, or translucent and jomted ; branches jointed, one-tubed, 
mostly pinnate (rarely dichotomous or irregular); dissepiments 
hyaline. Fruit of two kinds, on distinct plants; 1, external ¢etra- 
spores scattered along the ultimate branchlets, or borne on little 
pedicels; 2, roundish, or lobed, berry-like receptacles ( favelle) seated 
on the main branches, and containing numerous angular spores. 
CaLLitHAMNIoNn (Lyngb.),—from xaddos, beauty, and Gaynor, a little 
shrub. 
CatiitHaunton Pluma; stems rising from creeping filaments, erect, sub- 
simple, or alternately branched; branches naked below, the upper 
half pinnated with short, erect, closely set, opposite ramuli; articu- 
lations from two to four times as long as broad; tetraspores globose, 
either terminating shortened pinnules, or placed on little stalks near 
the base of the pinnule. 
CALLITHAMNION Pluma, 4g. Sp. Aig. vol. ii. p. 162. Harv. in Hook. Br. Fl. 
vol. ii. p. 340. Harv. in Mack. Fl. Hib. part 3. p.217. Harv. Man. ed. 2. 
p-173. #. Bot. Suppl. t. 2894. Endl. 3rd Suppl. p.34.  Kiitz. Sp. Alg. 
p- 647. 
CALLITHAMNION Plumula, @ pusillum, Lyngd. Hyd. Dan. p. 127. t. 39. 
Crramium Pluma, 4g. Syst. p. 132. 
ConFerva Pluma, Dillw. Conf. p.119. tab. F. 
Has. Parasitical on the stems of Laminaria digitata, rather rare. Annual. 
Summer. Bantry Bay, Miss Hutchins. Malbay, W.H.H. Appin, 
Capt. Carmichael. Probably overlooked on other parts of the coast. 
Groer. Distr. Atlantic shores of Europe. 
Descr. Forming velvety patches of some extent on the surface over which it 
spreads. Fronds rising from prostrate, creeping filaments, erect, from a 
quarter to half an inch or rather more in height, very slender, simple, or 
furnished with alternate or opposite, very erect branches: sometimes, in 
luxuriant specimens, almost bushy. Branches naked in their lower half, 
closely feathered above with opposite, erect, simple, straight ramuli, a pair 
of which issue from every articulation of the branch: ramuli, from suppres- 
sion, sometimes alternate or secund. Articulations of the stem from three 
to four times longer than broad, of the branches shorter; those of the 
ramuli frequently scarcely exceeding their diameter in length. Tetraspores 
globose, either borne on short, proper pedicels, which rise, singly or in 
pairs, near the base of the pinnules, or terminating a shortened pinnule : 
