SYNOPSIS OP SEAWEED TEIBES. 11 



Haeiseris — Frond forked, with a mid-rib. 



Padexa — Frond fan-shaped ; sori linear. 



Zoxaria — Frond lobed ; sori roundish. 



Taonia — Frond irregularly cleft, somewhat fan-shaped; sori 



linear 

 Dictyota — Frond linear, forked ; sori roundish. 

 Stilophoea — Fronds cylindrical ; spores forming a wart-like 



sori. 

 Dictyosiphon — Fronds tubular ; spores irregularly scattered, 



solitary, or in dot-like sori. 

 Strlaeua — Spores in sori, arranged across the frond in lines. 

 Punctaeia — Frond flat and leaf-like ; spores in small distinct 



dots. 

 Aspeeococcus — Frond tubular, cylindrical, or compressed; 



spores in dot-like sori. 

 Litosiphon — Frond cartilaginous, filiform; spores scattered. 



GENERA OF THE CHORDARIA TRIBE. 



Choedaeia — Frond, the central part firmly gelatinous. 



Mesogloia — Frond, the centre of the frond loosely gelatinous. 



Leatiiesia — Frond tuber-shaped. 



Ralesia — Frond crustaceous. 



Elachista — Filaments pencilled, rising from a tubercular base. 



Myrionema — Filaments rising from a flat base, minute. 



GENERA OF THE ECTOCARPUS TRIBE. 



Cladostephes — Stem not articulated, the ramuli alone 

 jointed and set in whorls. 



Sphacelaria — Stem articulated, branched; ramuli distich- 

 ous, pinnated. 



Ectocarpes — Stem jointed, very slender, hair-like, generally 

 much branched and flaccid. 



aTyriotrichia — Stem unbranched; ramuli in whorls, tipped 

 with transparent fibres. 



