Ser. EiiODOSPERMEiE. Fam. Rhodymeniacea. 



Plate XX. 



HYMENOCLADIA DIVARICATA, Haw. 



Gen. Char. Frond softly membranaceous, flat, linear, distichous, decom- 

 poundly pinnated, composed of three strata of cells ; the medullary 

 of large, roundish, inflated cells; the intermediate of smaller, angular 

 cells ; the cortical of minute, coloured cellules, arranged in vertical, 

 moniliform series. Friict. : 1, conceptacles globose, sessile, with a 

 thick, cellular pericarp, at length opening by an apical pore ; spore- 

 threads moniliform, attached to a basal placenta, the spores elliptic- 

 oblong; 2, dispersed, tripartite teiraspores. — Hymenocladia (/. Ag.), 

 from vfjbrjv, a membrane, and /cXaSos, a branch. 



Frons gelatinoso-rnembranacea, plano-compressa, linearis, distiche decomposito- 

 pinnata, stratis tribas contexta ; medullari ex cellulis magnis vesicatis, inter- 

 medio ex cellulis minoribus rotundato-angulatis pluriseriatis, corticali ex cel- 

 lulis miuiUissimis coloratis infila brevissima moniliformiaverticaUa conjunctis. 

 Cystocarpia intramarginalia, subsphcerica, sessilia, pericarpio crasso cellulari 

 demum ostiolo aperto, sporas oblongas in jila e placenta basali radiautia 

 evolutasfovetdia. Tetrasporce triangule divisa, sparsce. 



Hymenocladia divaricata ; frond rose-red, gelatino-membranaceous, de- 

 compound-pinnate ; rachis flexuous, narrowed at base and apex ; 

 pinnae and pinnulee linear-lanceolate, patent ; the ultimate ramuli 

 minute, setaceous, horizontal, closely set ; cystocarps marginal or in- 

 tramarginal ; tetraspores scattered in the cortical layer of the larger 

 branches. 



H. divaricata ; fronde plana rosea gelatinoso-membranacea decomposite pinnata ; 

 rachide fiexuosa basi et apice attenuata, pinnis pinnidisque lineari-lanceolatis 

 attenuatis patentibus, pinnulis idtimis setaceis minutis IwrizontaU-divaricatis ; 

 cystocarpiis submarginalibus sparsis ; tetrasporis magnis in ramis majoribus 

 vage immersis. 



Hymenocladia divaricata, Harv. in Trans. R. I. Acad. v. 22. p. 553. 

 Harv. Alg. Exsic. Austr. n. 364. 



Hab. Dredged in King George's Sound, and cast ashore at Middleton 



Bay, K.G.S., W. H. H. 

 Geogr. Distr. As above. 



Descr. Root a small disc. Fronds sub-solitary, 6-10 inches long, and nearly 

 as much in the spread of the branches, very much and closely branched in 

 a repeatedly pinnate order. The main rachis is not more than two lines in 

 breadth, tapering at each extremity, undivided, or once or twice forked, 

 nexuous, set throughout with horizontally patent, alternate branches of 

 very unequal length, short and long intermixed. These branches, like the 



