FUCACEiE. 11 



** Frond formed of jointed filaments, u'hich are either free or united 



into a compound body. 



5. Chordakiace.e. Frond cartilaginous or gelatinous, 

 composed of vertical and horizontal filaments inter- 

 laced together. Spores immersed. 



(>. EcTocARPACE^. Froncl filiform, jointed. Spores ex- 

 ternal. 



Order I. FUCACE^. 



J. Ag. Sp. Alg. vol. i. p. 180. C. Ag. Syst. Alg. p. xxxvii. 

 (in part). Decaisne, Ess. p. 34 (in part). Fucoideae, Grev. 

 Alg. Brit. p. 1. Harv. Matmal, 1 edit. p. 1. Fuceae, 

 Cystoseireae, Sargasseae and Halochloae, Kutz. Phyc. Gen. 

 p. 349. P\icidae and Cystoseiridae, Lindl. Veg. King. p. 22. 



Diagnosis. — Olive-coloured, inarticulate sea-weeds, whose 

 spores are contained in spherical cavities immersed in the 

 substance of the frond. 



Natural Character. — Root almost always a conical disk, 

 rarely branching or creeping. Fronds of an olive-brown or 

 olive-green colour, becoming darker in drying; of a tough, 

 leathery substance and fibrous texture, tearing lengthwise 

 with facility ; dichotomous or pinnate, rarely irregularly 

 branched, but very variable in habit. In the simpler kinds 

 {Splancnidium) there is no distinction into parts (as stem, 

 leaves and receptacle), but the fructification is equally dis- 

 persed through all parts of the plant ; in others [Durrill^a, 

 Sarcophycus) there is a stem ending in a phyllo-caulon or 

 leaf-like frond, through which the fructifications are scattered; 

 in others {HimantJialia) there is a .simple frond of small 

 size, and a branching receptacle of fructification resembling 

 a frond ; in others [Fucus, Cysioseira, &c.) there is a branch- 

 ing or imperfectly leafy frond, some portions of whose 

 branches finally swell, and are converted into receptacles of 

 fruit ; and finally, in the most perfect kinds {Sargassum, 

 Marginaria, &c.) there is a branching frond, with well- 

 formed, mostly distinct and nerved leaves, and receptacles 

 from their origin set apart as organs of fructification (not 

 formed by swellings of old branches), developed either in 



