Ser. Melanospekme.e. Earn. Fucacea. 



Plate IX. 



SCYTOTHALIA DORYCARPA, Grev. 



Gen. Chae. Root branching. Frond distichous, linear, ribless, alternately 

 decompound; the branches vertically flattened, phmatifid. Vesicles 

 none. Receptacles distinct, marginal, supra-axillary, flat, poriferous 

 on both surfaces; containing under each pore a monoecious spore- 

 cavity. Spores obovoid, sessile. Antheridia oval, on branching fila- 

 ments. Paranemata simple. — Scytothalia [Grev.), from a/euros, 

 leather, and Oako?, a branch. 



Radix ramosa. From disticha, linearis, costata, alterne decomposila, ramis ver- 

 ticalibus pinnatifidis. Vesicidat nulla. Receptacnla propria, secus margi- 

 nem evolida, supra-axillaria, plana (ovatav.lanceolata), utrinque osliolis per- 

 tusa. Scapliidia monoica. Spora obovoidem, subsessiles. Antheridia racemosa. 

 Paranemata simpliciuscula . 



Scytothalia dorycarpa, Grev. 



Scytothalia dorycarpa, Grev. Alg. Syn. p. xxxiv. Endl. 3rd Suppl. p. 33. 

 J. Ag. Sp. Alg. v. 1. p. 258. Kids. Sp. Alg. p. 592. Ilarv. Alg. Anstr. 

 Exsic. n. 28. 



Scytothalia xiphocarpa, ./. Ag. Sp. Alg. v. 1. p. 259. Kidz. Sp. Alg. p. 

 593. Ilarv. Alg. Austr. Exsic. n. 29. 



Cystoseira dorycarpa, Ag. Sp. Alg. p. 80 ; Syst.p. 292. 



Eucus dorycarpus, Turn. Hist. Fuc. t. 143. 



Hab. On rocks, just below low-water mark, and extending probably 

 throughout the Laminarian zone. Western Australia, Mr. Menzies, 

 Br. R. Brotvn. Abundant at Middleton Bay, King George's Sound, 

 and eastward to Cape Eiche, W. H. H. 



Geogr. Distr. South-west coasts of New Holland (not east of Cape Northum- 

 berland?). 



Descr. Root a flat disc, throwing out lateral, branching fibres. Fronds 1-3 

 feet long, linear, flat, coriaceous, distichous and alternately decompound, 

 the branches springing from the sharp edge of the primary stem. The pri- 

 mary stem is compressed and two-edged throughout, somewhat thickened 

 in the middle in its lower half, but nowhere distinctly midribbed. The 

 branches are 1-2 feet long, about two lines wide, slightly flexuous, and 

 alternately pinnatifid. The pinna? are either simple or again similarly com- 

 pounded ; old specimens becoming excessively branched aud dense, and oc- 

 casionally proliferous, from wounded parts. The ultimate pinnules are 3-6 

 inches long, linear-falcate, erecto-patent, and tapering to an acute point. 

 The receptacles spring along the margin of the secondary and tertiary 



