Ser. MELANOSPERMES. Fam. Fucacee. 
Puate CCC. 
DURVILLZA POTATORUM, resect. 
Grn. Cuar. Frond stipitate, without distinct organs, flat and expanded, 
palmately or pinnately divided, coriaceous. Spore-cavities scattered 
over the whole frond, hollowed out in the cortical stratum below the 
surface, spherical, communicating with the surface through a pore, 
dicecious. Spores obovoid, subsessile. Antheridia on branched, pa- 
rietal filaments, obovoid. Paranemata subsimple. 
yons stipitata, organis nullis discretis, exrpanso-plana, palmatim v. pinnatim 
Fi tipitata, org llis discretis, expanso-pl. palmat z t 
divisa, coriacea. Scaphidia per totam frondem sparsa, in strato corticali infra 
superficiem excavata, spherica, cum ostiolo superficialt per canalem communi- 
cantia, dioica. Spore obovoidee, subsessiles. Antheria in filis ramosis parie- 
talibus obovoidea. Paranemata subsimplicia. 
D’Urviti2a potatorum ; root scutate ; stipes short, compressed, expanding 
into a very long, strap-shaped, simple or forked, pinnated lamina; 
pinnee lanceolate, tapering to base and apex. 
_D. potatorum ; radice scutata, stipite brevi compresso in laminam longissimam 
ligulatam simplicem v. furcatam pinnatam solidam expanso ; pinnis lanceolatis 
basi et apice attenuatis. 
D’URvILLEA potatorum, Aresch. Alg. Exsic. 
Sarcopuycus potatorum, Azifz. Phyc. p. 392; Sp. Alg. p. 587. J. Ag. Sp. 
Alg.v.1.p.190. Hook. Fl. Tasm. v. 2. p. 286. 
LAMINARIA potatorum, Lamour. Ag. Sp. p. 115; Syst. p. 270. 
Fucus potatorum, Ladill. Nov. Holl. p. 112. ¢. 257. Turn. Hist. t. 242. 
Has. From Cape Northumberland to Cape Howe. Western and Northern 
coasts of ‘l'asmania. 
Geoer. Distr. South coasts of New Holland. Tasmania. 
Descr. Root a thick, scutate disc, when fully grown 4—6 inches in diameter, and 
nearly an inch thick. Stipes subterete at base, soon compressed, and widen- 
ing and flattening upwards till lost in the base of the lamina, 6-12 inches 
long, or more. Lamina, when fully grown, 12—24 feet long, or more, and 
nearly 4 inch thick, simple, or once or twice forked, the segments strap- 
shaped, of great length, 6-12 inches broad, and more or less copiously fur- 
nished with lateral lobes or pinnee, which sometimes are again lobulate. In 
some cases the division is nearly dichotomous throughout. Pixne lanceo- 
late, tapering to both ends, simple, or once or twice forked. Margins un- 
dulate. Spore-cavities scattered over the whole surface of the lamina. vi- 
sible only by their superficial pores, dicecious. I have not seen the female 
