SEii. GONGYLOSPEEMEvE. ( 167 ) Fam. CERAMIACEiE 



Plate CXXIII. 

 CALLITHAMNION TETPJCUM.— ^^. 



Gen. CnAR. — Fronds filiform and articulated, sometimes at length in the older parts 

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

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

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

 tripartite or cruciate. Name from kuAos, " beautiful," and Odfj.i'os, "a shrub." 



Callithamniojj tetriciim. — Fronds with a stem rather stout at the 

 base, and shaggy, tapering upwards to a point, much branched from the 

 base ; all the branches covered with plumulate ramuli, which are either 

 simply or doubly pinnate ; pinnae cylindi-ical, tapering at the base and 

 apex, bearing on the upper joints short, recurved, spine-like pinnules, on 

 which the tetraspores are placed. 



Callithamnion ^e<?'icM?)i-. — Aff. Sp. Alg. vol. ii. p. 179; Wyatt, Alg. Damn. 

 No. 141 ; Endl. 3rd. Suppl. p. 34 ; Harv. in Hooh Br. Fl. vol. ii. 

 p. 342 ; Harv. in. Mack. Fl. Nib. part 3, p. 214 ; Harv. P. B. 

 plate 188; Harv. Man. p. 176 ; Harv. Syn. p. 148; Atlas, plate 56, 

 fig. 259 ; /. G. Arjardh, S}^. Gen. Alg. vol. ii. p. 52. 



Phlebothamnion tetricum. — Kiitz. Phyc. Gen. p. 374. 



Conferva tetrica. — DUlio. t. 81 ; E. Bot. t. 1915. 



Hab. — On rocks from half- tide level to low- water mark. Perennial. Summer. 

 Common on the shores of the south of England, and south-west of Ireland — less frequent 

 on the east coast. Lambay {Mr. M'Calla) ; Channel Islands. 



Geogr. Dist. — Northern coasts of France. 



Description. — Root, a large flat conical disc, densely covered with 

 minute fibres. Frond much tufted, two to five inches or more in length, 

 and from half a line to one and a-half in thickness at the base, tapering 

 upwards, and repeatedly divided ; all the main divisions more or less 

 shaggy, especially towards the base, with "short, simple, or somewhat 

 elongated, slightly branched fibres ; ultimate ramuli pinnate, pinna) 

 alternate, rather long, cylindrical in the middle, tapering near the base 

 and apex, suberect or somewhat patent, of nearly equal length, giving 

 the plumule a linear appearance. Articulations about twice or thrice as 

 long as broad, those of the pinna) a little longer than broad, almost 

 cylindrical or very slightly inflated. Substance harsh and rigid, veiy 

 imperfectly adhering to paper. Colour, a dull sometimes dark reddish 



