374 
THE SEAWEEDS 
bb. Fronds compressed-plane or foliaceous. 
c. Fronds furcate or laterally branched. Spor- 
angia superficial, sparse. Filaments of 
medullary reticulum conjoined. Internal 
cortex lax, external firm, cells in anticlinal 
0Y der Grateloupia 
Agardli. 
.cc. Fronds entire or irregularly lobed. Sporangia 
superficial, sparse. Internal cortex lax, 
external thick, cells in anticlinal order . . Pachymenia 
J. Agardli. 
De Toni places the genus Epiphloea J. Ag. after Pachymenia. 
aa. Sporangia evolved in nemathecia. 
d. External cortex of minute cellules, in anti- 
clinal order. 
e. Fronds not net-like or perforated. 
f. Fronds linear, complanate, furcate or pin- 
nate. Medullary stratum firmly filamen- 
tous. Internal cortex lax, external 
dense 
ff. Fronds complanate, repeatedly furcate, 
here and there slightly constricted. 
Medullary stratum dense, filaments anas- 
tomosing. Cortex dense 
ee. Fronds reticulately perforated, more or less 
complanate, branched 
dd. Cortex of parenchymatous structure. 
g. Fronds below caulescent, simple, furcate or 
digitately laciniate, laciniae with a medium 
evanescent costa. Medullary filaments firm, 
laxly disposed. Cortex dense 
gg. Fronds furcate or laterally branched, margin 
and disc with prominent numerous horn- 
like processes, below with a median costa. 
Medullary filaments firm. Cortex dense . . 
Kutzing. 
Genus of doubtful position. 
Blastophye J. Agardli. Fronds carnose-plane, laciniae round, definite, 
from the margin or within proliferous, of three strata. 
Prionitis 
J. Agardh. 
Polyopes 
J. Agardh. 
Codiophyllum 
Gray. 
Cryptonemia 
J. Agardh. 
Tham noclonium 
