84 
THE SEAWEEDS 
e. Frond composed of several layers of 
cells (Pleiostromatic) . 
d. Striae of cortical cells radiating 
fanwise in pairs as if twinned. 
e. Sori naked. No paraphyses 
ee. Sori protected by an indusium. 
Paraphyses present . . . 
dd. Striae of cortical cells radiating 
fanwise singly. Sori without 
indusium but with paraphyses 
cc. Frond composed of two layers of cells 
(Distromatic) 
bb. Independent tufts of paranemata on the 
fronds. Cortical cells spaced equidis- 
tant from one another. ( Fronds flabel- 
late ; eeostate ; flat.) 
f. Fronds flat with entire margins, similar 
lobes prolificating from the upper 
surface of the frond. Spores 
forming interrupted zones 
ff. Frond erect, sub-dichotomous or 
palmatifid. Spores in sori, tetra- 
spores forming transverse zones . 
fff. Frond reniform-orbiculate, the edges 
involute, the lamina sometimes 
split into lobes. Spores and tetra- 
spores forming transverse zones . 
aa. Fronds erect, nowhere zoned with lines of 
innovation. 
g. 1 erminal cells of the frond numerous, 
radiating fanwise. 
h. Fronds without midrib (eeostate). 
Fronds subpalmate-dichotomous. 
Spores single or twinned evolved 
on both faces of the frond . . 
Gymnosorus 
J. Agardh. 
Zonaria (Drapar.) 
J. Agardh. 
Homveostrichus 
J. Agardh. 
Chlanidote 
J. Agardh. 
Lobophora 
J. Agardh. 
Taonia J. Agardh. 
Padina Adanson. 
S pat ho gl os sum 
Kuetzing. 
