Ser. Bjiodosperme/E. Fain. Rhodomelacece. 



Plate VIII. 



MARTENSIA AUSTRALIS, Haw. 



Gen. Char. Frond substipitate or sessile, membranous, nerveless, fringed 

 (at maturity) with au open network, formed of vertical and horizon- 

 tal anastomosing bars and cross-bars. Fructification : 1, ceramidia, 

 containing, within a membranous pericarp, a dense tuft of pear-shaped 

 spores ; 2, tetraspores, usually lodged in the cross-bars of the net- 

 work. — Martensia [Tiering), in honour of Professor Martens, of 

 Brussels. 



Frons substipitata v. sessilis, memb?'anacea, enervis, areolata, infra marginem (in 

 cetate majore) clathrato-fenestrata ; reticulo ex trabeculis verticalibus et ho- 

 rizontalibus formato. Fruct. : 1, ceramidia ; 2, tetrasporm triangule divisce 

 in Iambus verticalibus reticuli immerse. 



Martensia australis ; stipes cartilaginous, short, passing into the incras- 

 sated base of a many-lobed frond ; margin of the network toothed. 



M. australis ; stipite cartilagineo brevi in basi incrassata frondis multilobatce 

 membranacece desinente, margine reticuli dentato. 



Martensia australis, Harv. Trans. R. I. Acad. v. 22. p. 537 ; Alg. Austr. 

 Exsic. n. 111. 



Hab. Cast ashore. King George's Sound, W. H. H. Premantle, Western 



Australia, Mr. Clifton. Tasmania, Mr. Gunn and Rev. J. Fereday. 

 Geogr. Distr. Western Australia, and Tasmania. 



Descr. Boot a fleshy disc. Stipes from half an inch to an inch in length, carti- 

 laginous, compressed, one or two lines broad, becoming wider upwards and 

 gradually passing into the thickened base of the frond. Frond 4-8 inches 

 long (perhaps more ?), the membranous portion about 3 inches long and 

 broad, thin, delicately membranaceous, and areolated on the surface with 

 polygonal cellules. Network gradually developed ; in full-grown specimens 

 3-4 inches broad, lobed or frequently torn ; the meshes irregular in size, 

 usually longer than broad ; but small and large occur together. Margin of 

 the membrane entire or remotely denticulate ; that of the network narrow 

 and toothed or lacinulate. Ceramidia have not yet been found on this 

 species. Tetraspores are abundantly immersed in the longitudinal bars or 

 laminae of the network in our specimens, and are either cruciate or triangu- 

 larly parted. The substance is exceedingly thin and delicate, soon decom- 

 posing in fresh-water. The colour is a full, bright carmine or rose-red, and 

 well preserved in drying, in which state the plant adheres closely to paper. 



The genus Martensia was founded on an Alga (M. elegans) first 



