Ser. Rhodospeeme^. Fam. Rhodijmeniacea. 



Plate LXIII. 



PLOCAMIUM PREISSIANUM, Sond. 



Gen. Char. Frond membranaceo-cartilaginous, linear, piano-compressed, 

 pinnately decompound ; the pinnules alternately secund, in pairs or in 

 threes or fours ; composed of two strata of cells ; the inner cells ob- 

 long, longitudinal ; the outer polygonal, coloured, small. Fmctifica- 

 tion: 1, conceptacles sessile or pedicellate, hemispherical, with a cel- 

 lular pericarp finally opening by a pore ; sporiferous filaments nume- 

 rous, radiating in several tufts from a basal placenta ; 2, tetraspores 



lodged in proper spore-leaves [stichidia), oblong, transversely zoned. 



Plocamium [Lynghi), from ifkoKaiio^, a tuft of hair. 



Ifrons memhranaceo-cartilaginea, linearis, plano-compressa, pitmatim composita 

 pimiis alterne geminis ternis quaternisve, dupUci strata contexto ; cellulis 

 interioribus majorihiis oblongis longitudinalibus, siiperficialibus coloratis mi- 

 nutispolygonis. Fr. : 1, cystocarpia sessilia v. pedicellata, hemispliairica, peri- 

 carpio celltdoso demum carpostomio inHnita,Jila sporigera fasciculata a pla- 

 centa basali radlantia foventia ; 2, tetrasporce zonatim divisce, in sporophyllis 

 propriis nidulantes. 



Plocamium Preissiannm ; frond obsoletely costate, decompound-pinnate, 

 pinna3 and pinnules alternately ternate or quaternate ; the pinnules 

 cultrate, subacute, denticulate on the outer edge, slightly falcate • 

 spore-leaves fascicled in the axils of the pinnules, pedicellate, simple, 

 arched, acute at each end, with a single row of tetraspores ; concep- 

 tacles sessile, supra-axillary, warted. 



P. Preissianum ; fronde medio incrassata vix costata decomposito-pinnata, pinnis 

 pinnulisque alterne ternis quaternisve ; pinmdis cidtratis subfalcatis apice 

 extrorsum denticulatis acutiusculis ; sporophyllis axillaribus fascictdatis pedi- 

 cellatis simplicibus arcuatis basi et apice acutis, serie simplici tetrasporas qe- 

 rentibus ; cystocarpiis sessilibus supra-axillaribus verrucosis. 



Plocamium Preissianum, Sond. PI. Preiss. w. 2. jo. 192. KiUz. 8p. Ala. p. 885. 

 /. Jg. Sp. Alg. V. 2. p. 399. Earv. Alg. Austr. Exsic. n. 362. 



Hab. Western Australia, Preiss. Very abundant at King George's Sound • 

 and near Preemantle, and at Eottnest Island, West Australia, W.R.II., 

 G. Clifton, etc. South Australia, Br. Curdie. Western Port Vic- 

 toria, W. H. H. 



Geogb. Dist. Western and southern coasts of Austraha. 



DisTR. Root much branched. Fronds tufted, 1-2 feet high, and a foot or more 

 in expansion, somewhat flabelhform in outline, of a firmly membranous or 

 subcartilaginous substance, decompoundly branched, distichous, everywhere 



