319 
PL cell. aph. 2. THALASSIOPHYTiE. 
I. Thallus continued , fibrous , membranaceous or leather- 
like, purple or red ; sporidia immersed or in thecae, Floridese. 
Thallus flat, membranaceous, veined ; 
sporidia immersed and in tubercles .... Delesseria. 59. 
Thallus flat, membranaceous, veined; 
thecae podshaped, axillary Odonthalia. 60. 
Thallus flat, membranaceous, ribless ; 
thecae tubercular . Sph^erococcus. 61. 
Thallus linear, compressed or round, 
much branched ; thecae tubercular Gigartina. 62. 
Thallus linear, round or compressed ; 
sporidia immersed and in thecse Gastridium. 63. 
K. Thallus continuous, woody, fibrous, coriaceous; olive- 
brown becoming black ; sporidia in thecae or immersed . Fu- 
coidea. 
Ka. Sporidia superficial among gelatinous fibres. 
Thallus membranaceous, flat; 
fruit scattered ; holdfasts peltate Fascia. 64. 
Thallus leatherlike, flat; 
fruit scattered; holdfasts fibrous Laminaria. 65. 
Thallus leatherlike, flat; 
fruit on the stirps ; holdfasts fibrous .... Phasgonon. 66. 
Thallus threadlike, tubular, supple ; 
sporidia scattered on the surface Chorda. 67, 
Thallus threadlike, solid, branched ; 
sporidia scattered on the whole surface . . Chordaria. 68. 
Kb. Sporidia in scattered, immersed thecae . 
Thallus threadlike, cartilaginous .... Sporochnus. 69. 
Thallus compressed, membranaceous Desmarestia. 70. 
Kc. Sporidia in a terminal theca. 
Thallus shrubby, compressed Lychina. 71. 
Kd. Sporidia in thecae, immersed on an apothecium. 
Thallus cupshaped ; vesicles 0; 
apoihecia compressed, forked Himanthalia. 72. 
Thallus round, forked, ribless; 
vesicles 0 ; apoihecia terminal Cervina. 73. 
