Ser. Melanospermejs. Fam. Chordariea. 



Plate CCCXXIV. 



LEATHESIA TUBERIFORMIS, 8. F. Gray. 



Gen. Char. Frond globose or lobed, fleshy, composed of jointed, colour- 

 less, dichotomous filaments, issuing from a central point; their 

 apices, which constitute a fleshy coating to the frond, coloured and 

 tufted. Fructification, oval or pyriform spores, concealed among 

 the coloured apical filaments. Leathesia (S. F. Gray), — in honour 

 of the Rev. G. R. Leathes, a British naturalist ; and who first com- 

 municated this plant to Sir J. E. Smith. 



Leathesia tuberiformis ; fronds olivaceous, tuberous, when young stuffed 

 with cottony fibres, at length hollow. 



Leathesia tuberiformis, S. F. Gray, Nat. Jr. Br. PI. vol. i. p. 301. Harv. 

 Man. ed. 2. p. 48. 



Leathesia marina, Endl. 3rd Supp. p. 23. Kiitz. Sp. Alg. p. 543. /. Ag. 

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



Leathesia difforriris, Aresch. Enum. Phyc. Scand. p. 154. t. 9. f. B. 



Cokynephora marina, Ag. Syst. p. 24. Harv. in Hook. Br. Fl. vol. ii. 

 p. 390. Harv. Man. ed. 1. p. 46. Wyatt, Alg. Danm.. no. 149. Grev. 

 Crypt. Scot. t. 53. Harv. in Muck. Fl. Hid. part 3. p. 184. 



Ch^tophora marina, Lyngb. Hyd. Dan. p. 193. t. 66. 



Nostoc marinum, Ag. Bisp. p. 45. et Syn. p. 133. 



Tremella difformis, Linn. Syst. Nat. p. 714. Huds. Fl. Ang. vol. ii. p. 565. 



With. vol. iv. p. 82. 

 Uivularia tuberiformis, E. Bot. t. 1956. 



Uab. Between tide-marks, on rocks, corallines, and the smaller Algas; 

 very common. Annual. Summer and autumn. 



Geogr. Distr. Atlantic shores of Europe. Baltic Sea. East coast of North 

 America. Cape of Good Hope, common, W. II. H. 



Descr. Fronds when growing on Algae scattered or solitary, when on rocks 

 usually heaped together and much crowded, forming wide-spreading tuber- 

 culated masses, very variable in size, from that of a pea to that of a large 

 walnut. When young, the interior of the tuberous frond is stuffed with 

 weak, empty, dichotomous, cobweb-like fibres, rising from the base and 

 radiating in all directions, but as the outer wall extends, these gradually 

 perish, and the plant becomes a hollow ball. The lowermost cells of the 

 cobwebby fibres arc very long and slender ; the upper ones become 

 gradually shorter and wider, and are two-horned, or somewhat half-nioon- 

 shaped, a new cell springing from each cusp ; those which adjoin to the outer 

 wall arc small and globose. The outer wall is formed of closely-packed, 

 niouilifonn, club-shaped, vertical filaments, lying in a transparent jelly; 

 each filament formed of several Bpherical ©ells containing olive granules. 

 Spores pyriform, sunk among the club-shaped peripheric filaments, with 



