GYMNOGONGRUS. 145 



VII. GYMNOGONGRUS. Mart. [Plate 18, B.] 



Frond cylindrical or compressed, horny, much branched, 

 its substance composed of densely packed filaments, of which 

 the innermost are longitudinal, the middle curving outwards, 

 and the external stratum (or periphery) horizontal and mo- 

 niliform. Fructification naked warts entirely composed of 

 bead-like strings of cruciate tetraspores. Name, from yv^vog, 

 naked, and yoyypog, a word applied by Theophrastus to the 

 wartlike excrescences often seen on trees. 



1. G. Griffithsice, Turn. ; frond filiform, flexuous, carti- 

 laginous, stipitate, many times dichotomous, the apices 

 fastigiate, forked, warts of fructification oblong, at length 

 surrounding the stem. Grev. Alg. Brit. p. 149 ; Hook. Br. 

 Fl. ii. p. 301 ; Wyait, Alg.' Danm. No. 28 ; Harv. Phyc. 

 Brit. t. cviii. Fucus Grijfit/tsice, E. Bot. t. 1926. 



On rocks in the sea. Perennial. Autumn and winter. Coast of De- 

 vonshire, Mrs. Griffiths. Bantry Bay, Miss Hutchins. Balbriggan, Dr. 

 Scott. Orkney. Fronds tufted, entangled, 2 4 inches high, slender and 

 filiform, many times dichotomous, the axils patent, the apices nearly of 

 equal length, giving the plant a rounded outline ; branches flexuous, of 

 equal diameter throughout, obtuse. Fructification, so far as known, con- 

 sisting of oblong warts, surrounding the stem, composed of articulated 

 filaments, whose cells are afterwards changed into cruciate tetraspores, 

 strung together like beads. Each tetraspore is brilliant as a ruby, and 

 marked with a slender St. George's cross. Substance cartilaginous, some- 

 what horny when dry. Colour a dull purplish-red, 



2. G. ? piicata, Huds. ; frond horny, cylindrical, filiform, 

 very irregularly branched, entangled, wiry ; branches sub- 

 dichotomous ; axils obtuse ; ramuli often secund ; fructifica- 

 tion, oblong warts composed of obscurely jointed filaments. 

 Grev. Alg. Brit. p. 150; Hook. Br. Fl. ii. p. 301; Wyatt, 

 Alg. Danm. No. 116; Harv. Phyc. Brit. t. cclxxxviii. Fu- 

 cus plicatus, E. Bot. t. 1089. 



On rocky sea shores. Perennial. Fronds 4 10 inches long, entangled, 

 rigid and wiry, cylindrical, as thick as hogs' bristles, of equal diameter 

 throughout, irregularly branched, dichotomous, with very rounded axils, 

 more or less furnished with horizontal ramuli, which sometimes spread in 

 all directions. Fruit, as far as known, oblong warts embracing the stem, 

 and composed of very slender jointed threads ; but I have never succeeded 

 in finding spores or tetraspores. The structure in this plant is very much 

 more dense than in G. Griffithsiee, and the filaments of which it is com- 

 posed much more slender. Colour a blackish purple, whitish in decay. 



