14 SYNOPSIS OF SEAWEED TItlEES. 



Rhodymenia — Tubercles convex, scattered ; frond flat. 

 Sphjerococctjs — Frond linear, compressed, and disticliously 



branched. 

 Gracilaria. — Frond filiform, compressed or flat, irregularly 



branched, the central cells large. 

 Hypnea — Frond filiform, irregularly branched, traversed by a 



fibro-cellular axis. 



GENERA OF THE CRYPTONEMIA TRIBE. 



Gbatelottpia — Frond pinnated, flat, narrow ; between mem- 

 branaceous and cartilaginous ; structure very dense ; favel- 

 lidia in the branches ; tetraspores scattered. 



Gelidium — Frond pinnated, compressed, narrow, horny ; fa- 

 vettidia in swollen ramuli. 



Gigartina — Frond cartilaginous, cylindrical, or compressed ; 

 favellidia in external tubercles; tetraspores sunk in the 

 frond. 



Chondrus — Frond fan-shaped, dichotomously cleft, cartila- 

 ginous ; tetraspores in sori immersed in the frond. 



Phyllophora — Frond stalked, rigid, membranaceous, proli- 

 ferous from the disc ; tetraspores in sori or in proper leaflets. 



Peyssoxelia — Frond depressed, expanded, rooting by the 

 under- surface. 



Gyylnogongrtjs — Frond filiform, dichotomous, horny; tetra- 

 spores strung together, contained in a wart-like sori. 



Polyides — Root scutate ; frond cylindrical, cartilaginous, 

 forked ; favellze in spongy external warts ; tetraspores 

 scattered through the outer stratum of the frond. 



Furcellaria — Root branching; frond cylindrical, dichoto- 

 mous, cartilaginous; favellss unknown; tetraspores con- 

 tained in the swollen pod- like upper branches of the frond. 



Dumoxtia — Frond cylindrical, tubular, membranaceous, of a 

 dull red colour. 



Haly:\iexia — Frond either compressed or flat, of a gelatinous 

 membranaceous structure and pinky-red colour. 



Gixnania — Frond cylindrical, dichotomous, traversed by a 

 fibrous axis. 



