Ser. MELANOSPERMEiE. (117 ) Fam. CHORD ARIEvE. 



LEATHESIA TUBEEIFORMIS.— «. F. Gray. 



Gen. Char.— Frond cellular, fleshy, more or less globose ; cells of the central portion 

 cylindrical, arranged in radiating dichotomous series ; those of the outer portion 

 forming tufted, club-shaped, moniliform filaments. Fructification : obovate spores, 

 produced at the bases of the apical filaments. Name in honour of the Rev. 

 G. R. Leathes. 



Leathesia tuberiformis. — Fronds, when young, spherical and solid, 

 the centre filled with loose jointed fibres ; when old irregularly roundish 

 and hollow. 



Lkathesia. tiiberiforviis. — S. F. Gray, Nat. Ar. Br. PI. vol. i. p. 301 ; Harv. P. B. 

 plate 324; Harv. Man. p. 48; Harv. Syn. p. 42; ^^Zas, plate 13, 

 fig, 54 ; Harv. N. B. A. part 1, p. 129. 



Leathesia marina. — Endl. 3rd Suppl. p. 23 ; Kiltz. Sp. Air/, p. 543 ; /. G. Agardh, 

 Sp. Gen. Alg. vol. i. p. 52. 



Leathesia difformis. — Aresch. Enum. Phyc. Scand. p. 154, t. 9, f. b. 



CoRYNEPHORA marina. — Ag. Syst. p. 24 ; Harv. in Hooh. Br. Fl. vol. ii. p. 390 ; 

 Harv. Man. 1st edit. p. 46; Wyatt, Alg. Danm. No. 149; Grev. 

 Crypt. Scot. t. 53 ; Harv. in Mack. FL Hib. part 3, p. 184. 



Ch.s:tophora marina. — Lyngb. Hyd. Dan. p. 193, t. 66. 

 NosTOO marinum. — Ag. Disp. p. 45, et Syn. p. 133. 



Tremella difformis. — Linn. Syst. Nat. p. 714 ; Huds. Fl. Angl. vol. ii. p. 565; 

 WUh. Br. PI. vol. iv. p. 82. 



RivuLARiA tuberiformis. — E. Bot. t. 1956. 



Hab. — On rocks, corallines, and the smaller Algffi, between tide-marks. Very common. 

 Annual. Summer and autumn. 



Geogr. Dist. — Atlantic shores of Europe ; Baltic Sea ; East coast of North America ; 

 Cape of Good Hope, common {Dr. Harvey). 



Description. — Root discoid. Fronds crowded or solitaiy, when young 

 more or less spherical or obovate and solid, the central portion occupied 

 with loosely interwoven jointed filaments, which eventually decay and 

 leave the frond more or less hollow. Its inner portion is then composed 

 of a stratum of radiating dichotomous filaments, formed of rather long 

 cylindrical joints, and that is succeeded by a stratum of dichotomous 

 filaments, of which the forhed cells themselves foi-m the bases of the 

 dichotomies. The periphery composed of tufts of densely packed, club- 

 shaped, simple, moniliform, coloured filaments. Substance subcartila- 

 ginous, but soft and adhering closely to the paper. Colour brownish 



