Ser. EhodospermejE. Fam. Laure^iciacea. 



Plate CXLVllL 



LAURENCIA HETEEOCLADA, Haw. 



Gen. Char. Frond cylindrical or piano-compressed, linear, pinnatelj- 

 branched, cartilaginous, the apices obtuse, composed of two strata 

 of cells; the inner of oblong, angular cells, shorter toward the cir- 

 cumference ; the oiiter of small, roundish-angular cellules. Fruit : 



1, ovate, sessile ceramidia, containing a tuft of pear-shaped spores; 



2, tripartite tetraspores, imbedded, without order, beneath the tips of 

 the ramuli. — Lauren cia [Lamour.), in honour of M. De la Laurencie, 

 a French naturalist. 



Frons teretiuscula v. plano-compressa, linearis, pinnato-ramosa, cartilaginea, 

 apicihus obtusis, ex stratis duobus contexta, strata medullari ex cellidis oblongis 

 extus sensim brevioribns, corticali ex cellulis minoribus rotiindo-angulatis colo- 

 ratis. Friict. : 1, ceramidia ovata, sessUia, intra pericarpiiim crassiuscidum 

 fascicidiivi sporarum pyriformiiim foventia ; 2, tetrasporce triangule divisce, 

 infra apicem ramulorimi sine ordine immersce. 



Laurencia Jieteroclada ; densely tufted, springing from creeping shoots ; 

 frond livid-purple, terete, rigid, tough, the younger many times se- 

 cundly branched, with very erect branches and branchlets and very 

 narrow axils ; the adult panicled above, the branches issuing toward 

 every side, long and spreading; ramuli alternate, spirally inserted, 

 corymbose, multifid ; ceramidia ovate, sessile ; tetraspores apical, in 

 short, swollen ramuli. 



L. heteroclada ; densissime ccespitosa, e surculis repentibus orta ; fronde livido- 

 purpurea tereti rigida tenaci, juniori pluries secunde v. subsecwide ramosa ; 

 raniis ramnlisque erecto-appressis axillis angustissimis ; adulta apice panicu- 

 lata, rainis quoquoversuni egredientibus elongatis patentibus ; ramulis alternis 

 spiraliter insertis coryynboso-multifidis ; ceramidiis ovatis sessilibus ; tetra- 

 sporis in apicibus incrassatis ramulorimi immersis. 



Laurencia heteroclada, Harv. in Trans. R. I. Acad. v. 23. p. 544 ; Alg. Exsic. 

 Austr. n. 234. 



Hab. Covering the exposed edges of reefs at low water-mark, spreading 

 continuously over wide spaces. Eottnest Island, W. H. H. Fremantle, 

 G. Clifton. Port Pairy, Cape Eiche, and Western Port, IF. H. H. 



Geogr. Distr. Western and southern coasts of Australia. 



Descr. Roots forming a continuous mass of creeping interwoven fibres, spread- 

 ing over large spaces. Fronds densely tutted, 4-8 inches high, rather 

 thicker than hog's-bristle, cylindrical, very rigid and tough. The young, 

 immatuve fronds, 2-3 inches in height, are closely set with lateral, generally 



