VI SYNOPSIS OF THE 



Order 4. Dictyotace^e. Olive-coloured, inarticulate seatveeds, whose spores 

 are superficial^ disposed in definite spots or lines fsorij. 



* Root coated with woolly fibres, frond flat. 



XIV. Cutleria. Frond ribless, irregularly cleft. Sort dot-like, scattered. 

 Spores pedicellate, containing numerous sporules. 



XV. Haliseris. Frond midribbed. 



XVI. Padina. Frond ribless, fan-shaped, concentrically striate. Son linear, 

 concentric, bursting through the epidermis. 



XVII. Zonaria. Frond ribless, lobed, concentrically striate. Sori roundish, con- 

 taining spores and jointed threads. 



XVIII. Taonia. Frond ribless, irregularly cleft, somewhat fan-shaped. Sori 

 linear, concentric, superficial, alternating with scattered spores. 



XIX. Dictyota. Frond ribless, linear, dichotomous. Sori roundish, scattered, 

 bursting through the epidermis : or, (on distinct plants) scattered spores. 



* * Root a minute naked disc. Frond cylindrical, branched. 



XX. Stilophora. Spores concealed among moniliform threads, which are col- 

 lected into convex, wart-like sori. 



XXI. Dictyosiphon. Spores irregularly scattered, solitary, or in dot-like sori, 

 not accompanied by moniliform threads. 



XXII. Striaria. Spores in dot-like sori, ranged in transverse lines. 



* * * Root naked. Frond unbranched, cylindrical, or flat. 



XXIII. Punctaria. Frond flat, leaf-like. 



XXIV. Asperococcus. Frond membranaceous, tubular, either cylindrical or 

 compressed. Spores in dot-like sori, mixed with a few jointed threads. 



XXV. Litosiphon. Frond cartilaginous, filiform, sub-solid. Spores scattered, 

 sub-solitary. 



Order 5. Chord ariace^e. Olive-coloured seaweeds, with a gelatinous or 

 cartilaginous frond, composed of vertical and horizontal filaments inter- 

 laced together. 



* Frond cylindrical, branching. 



XXVI. Chordaria. Axis cartilaginous, dense ; filaments of the circumference 

 unbranched. 



XXVII. Mesogloia. Axis gelatinous, loose ; filaments of the circumference 

 branching. 



* * Frond either tuber-shaped, or crustaceous and spreading. 



XXVIII. Leathesia. Frond tuber-shaped. 



XXIX. Ralfsia. Frond crustaceous. 



* * * Parasites, consisting of densely tufted filaments, connected at the base, free above. 



XXX. Elachista. Filaments pencilled, rising from a tubercular base, composed 

 of vertical fibres. 



XXXI. Myrionema. Tufts cushion-like ; filaments rising from a flat base, com- 

 posed of decumbent fibres. 



Order 6. Ectocarpace^e. Olive-coloured, articulated, filiform seaweeds, 

 whose spores are (generally) external, attached to the jointed ramuli. 



* Frond rigid; each articulation composed of numerous cells. 

 XXXTI. Cladostephus, Ramuli whorled. 



