Seu. GONGYLOSPERME^. ( 185 ) Fam. CERAMIACE/E. 



CALLITHAMNION GEACILLIMUM.— ^r/. 



Gen. Char. — Fronds filiform and articulated, sometimes at lengtli in the older parts 

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

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

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

 tripartite or cruciate. Name from KaXhs, "beautiful," and Od/xvos, "a shrub." 



Callithamxion graciUimum. — Fronds tufted, much branched disti- 

 chously, capillaceous, tapering, decomposite- pinnate ; pinuse alternate, 

 erecto-pateut ; articulations nearly cylindrical, those of the stem three 

 to five times, of the pinnse and pinnulse two to thi-ee times longer than 

 broad, shorter upwards ; tetraspores terminal on the apices of the upper 

 pinnulae. 



Callithamnion graciUimum. — Ag. Sp. Alg, vol. ii. p. 1(!8 ; Wyatt, Alg. Danm. 

 No. 45 ; Endl. 3rd Suppl. p. 34 ; KUtz. Phyc. Gen. p. 372 ; Harv. 

 in Hook. Br. Fl. vol. ii. p. 345 ; Harv. P. B. plate 5 ; Harv. Man. 

 p. 180 ; Harv. Syn. p. 153 ; Atlas, plate 59, fig. 274 ; /. 6. Agardh, 

 Sp. Gen. Alg. vol. ii. p. 43. 



Hab. — On mud-covered perpendicular rocks, near low-water mark. Annual. Summer. 

 Rare. On the pier at Torquay {Mrs. Gi-iffiths) ; Milford Haven {Mr. Ralfs) ; Falmouth 

 {Miss Warren) ; Beaumaris {Mrs, Gulson and others). 



Geogr. Dist. — Atlantic coast of France ; Grateloup ; south and west of England. 



Description. — Fronds much tufted, veiy slender and delicate, two to 

 four inches long, capillaceous, much branched in a regularly distichous 

 and alternately pinnate manner; primaiy pinnae long, naiTow, pinnules 

 longest at the base, gradually shorter upwards, repeatedly pinnate, all 

 the divisions erecto- patent, regularly alternate and distichous, every 

 articulation generally producing its ramulus, all tapering to an obtuse 

 point. Articulations of the stem and main branches three to four times 

 as long as broad, gradually shorter upwards, nearly cylindi-ical, or 

 slightly contracted above the middle and at the dissepiments. Substance 

 veiy delicately membranous, and closely adhering to the paper. Colour, 

 a fine deep rose i-ed, readily discharged in fresh water, and giving out a 

 " quantity of brilliant carmine powder, which permanently stains paper." 

 Favellee " roundish or irregularly lobed, springing from the larger 

 branches." Tetraspores teniiinal on the tips of the ultimate ramuli or 

 pinmda), very minute, not unfrequent, while the favella? seem very rare, 

 and seldom abundant even when present. 



VOL. II, B B 



