Rer. GOXGYLOSPET^i\IE.T;. (ir,7) Fam. CERAMIAOE/E. 



CALLITHAIMNION VLVUA.'—Aff. 



Gen. Char. — Fronds filiform and articulated, sometimes at length in tlie older parts 

 cellular and partially opaque, single-tubed ; divisions mostly pinnate, dissepiments 

 hyaline. Fructification of two kinds, on distinct plants : 1. Favellse, mostly 

 lateral on the lirauchcs, and filled with minute spores ; 2. Tetraspores, external, 

 trijiartite or cruciate. Name from /caA.bj, " beautiful, " and 0ayu>'oy, "a shrub." 



Callithammon 2)luma. — Stems arising from creeping fibres, erect, 

 sparingly branched, naked below, closely pectinato-pinnate at the 

 summits with short, rather erect, opposite ramuli ; articulations about 

 two but sometimes four times as long as broad ; tetraspores terminal on 

 abbreviated ramuli, or attached to short proper stalks near their base. 



Callithamnion ^Zwwia. — Ag, Sp, Alg. vol. ii. p. 162; E, Bot. Suppl. t. 2894; 

 £ndl. 3rd Suppl. p. 34; Kiltz. Sp. Alg. p. 647; Ilarv. in Jlooh. 

 Br. Fl. vol. ii. p. 340 ; JIarv. in 3fack. Fl. Bib. part 3, p. 217 ; 

 ITarv. P. B. plate 296; Harv. Man. p. 173; Haw. Syn. p. 145; 

 Atlas, plate 58, fig. 267 ; /. G. Agardh, Sjy. Gen. Alg. vol. ii. p. 25. 



Callithamnion plumula, /3 pusillum. — Lyngh. Hyd. Dan. p. 127, t. 39. 



Ceramitjm pluma. — Ag. Sysf. p. 132. 



Conferva pluma. — Dillw. Conf. p. 119, tab. F. 



Hab. — Parasitical on the stems of Laminaria digitata. Not uncommon. Annual. 

 Summer. No doubt on all our coasts. 



Geoor. Dist. — Atlantic shores of Europe. 



Description. — Root composed of creeping fibres, attaching itself to 

 the stems of other plants by means of minute discs. Fronds densely 

 tufted, erect, two to six lines or so in height, very slender, often simple, 

 generally sparingly branched ; the branches alternate, furnished at their 

 summits with short, opposite, closely placed, pectinato-pinnate ramuli, 

 each joint furnishing a pair, the lower ones longest, ujjper minute, form- 

 ing an ovate plumule, which is frequently imperfect. Articulations of 

 the stem variable, generally about twice as long as broad, those of the 

 ramuli rather shorter, and their diameter not much less than that of 

 the main stems, all cylindrical, apices very obtuse, " Tetraspores globose, 

 either borne on short, proper pedicels, T^hich rise singly or in pairs, near 

 the base of the pinnules, or terminating a shortened pinnule." 



This very pretty and vciy minute species is considered rather rare, 

 but may be often overlooked on account of its small size and simple 



