Ser. IIhodospeeme^. Fam. RkodomelacecB. 



Plate CXXIV. 



DICTYMENIA FRAXINIFOLTA, Harv. 



Gen. Char. Frond flat, membranaceous, midribbed, alternately decom- 

 pound, pinnatifid or rarely foliiferous, areolate ; the medullar^/ cells 

 large, twelve-sided, colourless, transversely set ; the cortical minute, 

 irregular, coloured. Fructification : 1, ovate, stipitate ceramidia, 

 containing a tuft of pear-shaped spores ; 2, simple or branched sfi- 

 ckidia, containing tripartite tetraspores. — Dictymenia (Grev.), from 

 StfCTVov, a net, and vixr^v, a membrane, because the membrane appears 

 areolated (under a low mngnifyhig power). 



Frons plana, memhranacea,co8tata,alterne decompoHita, pinnatifida v. rarofolii- 

 fera, areolata ; strata mednllari ex cellulis magnis Jiyalinis dodecahedris 



transversim ordiuatis, corticati ex cellulis mintitis coloratis irregularibus 

 formato. Frtict. : 1 , ceramidia pedicellata ; stichidia propria, simplicia v. 



raiHOsa, tetrasporas \-2-seriatastriangide divisas foventia. 



Dictymenia fraxinifolia ; stem cylindrical, thick and rigid, branched, 

 the branches bearing leaves; leaves {p//j/llodia) oblong, obtuse at 

 each end, midribbed and closely penninerved, sharply serrulate ; 

 nerves setigerous, midrib serrated; stichidia linear, simple or com- 

 pound, mucronate, borne on the nerves. 



D. fraxinifolia ; caule cylindraceo crasso diiro ramoso, ran/is foliiferis, foliis 

 (pliyllodds) ohlongis basi et apice obtusis costatis et creberrime peuninerviis 

 argute serrulatis, nervis setigeris, coda serrata, stickidiis linearibus Jtuicronatis 

 simplicibus compositisve e nereis euatis. 



Dictymenia fraxinifolia, Harv. in Trans. R. I. Acad. v. 22. p. 538. 



Epineuron fraxinifolia m, Harv. MSS. K'utz. Sp. Alg. p. 849. 



Amansia fraxinifolia, Ag. Syst. Alg. p. 247- 



Delessekia fraxinifolia, Grev. Syn. p. xlvii. 



Fucus fraxinifolius, Mert. Tarn. Hist. t. 193. 



Hab. Hottnest Island, Western Australia, W. H. H., G. Clifton. 



Geogr. Distr. Peninsula of India, and Ceylon. Western Australia. 



Descr. Root a hard, knobby disc or bulb. Stem (formed out of the thickened 

 and denuded midrib of a primordial phyllodiura) 3-6 or 8 inches long, 

 \ line to 1|^ line in diameter, very rigid, woody when dry, simple or irre- 

 gularly branched, the branches more or less winged with the remains of a 

 dilapidated lamina. Leaves either continuous with the branches, or spring- 

 ing irregularly from their sides, 3-6 inches long, f-1 inch wide, rigidly 



