8er. liiiODOSPERME^. Fam. Uhodowelucea. 



Plate CXXX. 



RHODOMELA? SPINULOSA, Haw. 



Gen. Chae. Frond terete, dendroid, inarticulate, solid, coated with minute 

 polygonal cellules; the axis articulated, polysiphonous. Fructifica- 

 tion : 1, ovate ceramidia containing a tuft of pear-shaped spores ; 2, 

 tetraspores lodged in swollen ramuli or in pod-like stichidia, in a sin- 

 gle or double row. — Ehodomela [Ag.), from poBeo^, red, and /xe\a9, 

 lilac^ ; because these plants become darker in drying. 



Frons teres, dendroidea, iuarticulata, solida, cellulis minidis polygonis corticata ; 

 axi articulato, polysiphonio. Fruct.: 1, ceramidia ovata, sporas pedicellatas 

 fascicidatas pyriformes foventia ; 3, tetrasporce triangide divisce, in ramulis 

 immersae v. in stickidiis propriis evoluta. 



Ehodomela apinulosa ; frond robust, dendroid, decompoundly much- 

 branched J branches and ramuli erecto-patent, spreading to all sides, 

 vaguely divided ; ramuli short, spine-like, scattered ; ceramidia ter- 

 minal. 



R. spinulosa ; fronde crassa dendroidea decomposite ramosissima ; raniis ramu- 

 lisque erecto-patentibus quoquoversiim sistentibiis vage divisis ; raimdis brevibus 

 spinaformibus sparsis; ceramidiis ramulos terminantibus. 



Alsidium? spinulosum, Harv. Alg. Austr. Exsic. n. 138. 



Hab. Cast ashore from deep water. Garden and Eottnest Islands, near 



Fremantle, and on the shore at Cape Eiche, W. II. H. 

 Geogr. Distr. Western and south-western coasts of Australia. 



Descr. Root? Frond 10-12 inches long, very much branched, and bushy, 

 tree-like, with a robust, deliquescent stem, nearly a line in diameter at base, 

 gradually tapering upwards, and breaking up above into many slender 

 branches. The ramification is very irregular, in no part pinnate or dicho- 

 tomous, and more inclining to a subspiral, alternate division than to any 

 other. The branches spring from all sides of the stem, and are directed 

 every way ; they are 3-4 times decompound, and set at short intervals with 

 spine-like ramuli. Ramuli 1-2 lines long, erecto-patent, subulate, acute, quite 

 simple. Conceptacles rare, ovate, terminating the ramuli. Stichidia unknown. 

 Every part of the plant, when examined under the microscope, is opaque 

 and coated with small, oblong cellules ; but in the dried frond, viewed un- 

 der a pocket-lens, there is a faint appearance of transverse striae in the younger 

 branches and ramuh. A transverse section shows fom- large tubes surround- 

 ing the axile cell, and filled with dispersed granules ; and a coating of 



