Ser. RhodospeumejE. Tam. Spharococcoidecs ? 



Plate CCXI. 



THYSANOCLADIA LAXA, Sond. 



Gen. Char. Frond flat or compressed^ distichously decomposito-pinnate, 

 formed of three strata of cells ; the medullary of densely interwoven, 

 slender, longitudinal filaments ; the intermediate of roundish-oblong 

 cells ; the cortical of minute, vertically arranged cellules. Fructifi- 

 cation : 1, half-immersed conceptacles, containing, within a thick peri- 

 carp, minute spores arranged in spore-threads radiating from a large 

 placenta ; 2, tetraspores ? — Thysanocladia {EiidL), from 6vaavo<;, 

 a fringe, and /cA,a8o9, a branch. 



Frons plana v. compressa, distiche decomposito-pinnata, iriplici strata contexta; 

 medullari fiUs longitudirtalibus tenuibiis articulatis densissime intertextis, in- 

 termedio cellulis majusculis rotundato-ohlongis, corticali cellulis minimis ver- 

 ticaliier seriatis coloratis composito. Fruct. : 1, cystocarpia semi-immersa, 

 intra pericarpium crassum sporas minutas in filis a placenta magna radian- 

 tibus ordinatis foventia ; tetrasporce ? 



Thysanocladia laxa ; frond livid-purple, drying brown, flat, below thick- 

 ened in the centre, and sometimes ribbed, quite ribless above, dis- 

 tichously decompound-pinnate ; pinnge broadly linear, approximate, 

 patent, subopposite ; pinnules suberect, broadly linear, flat, narrowed 

 at base, simple or 3-forked, or pinnulate ; axils of the pinnse rounded ; 

 sori of tetraspores in the dilated apices of the branches. 



T. laxa ; fronde livido-purpurea siccltate fuscescente plana, inferne medio-incras- 

 sata V. subcostata, superne ecostata, distiche decomposito-pinnata ; pinnis lato- 

 linearibiis approximatis patentibus oppositis ; pinmdis erectiusculis lato-linea- 

 ribus planis basi angustatis simplicibus v. trifurcis pinnidatisve ; axillis pinnu- 

 larum eximie rotundatis ; soris tetrasporarum in apicibiis dilatatis immersis. 



Thysanocladia laxa. Sond. in Linn. v. 25. p. 689. Harv. in Trans. R. I. 

 Acad. V. 22. p. 550. Sarv. Alg. Austr. Exsic. n. 310. 



Hab. Eivoli Bay, Dr. Mueller ! Eottnest, West Australia, W. H. H. 



Geogk. Distr. Western and southern coasts of Australia. 



Descr. Root . . . ? Fronds about a foot in height, and as much in the expan- 

 sion of the branches, 1-3 lines wide, terete at base for one or two inches, 

 thence upwards quite flat and nerveless, or merely thickened in the centre, 

 pinnately decompound, distichous. Pinna patent or subhorizontal, the 

 lowest longest, the upper gradually shorter, opposite or nearly so, close 

 together or shghtly distant, all naked for a short distance at base, and 

 oppositely pinnate or bipinuatc in their upper part. All the axils and 

 apices arc remarkably obtuse : the lesser pinna; are somewhat, but not 

 greatly narrower than the larger, and all are perfectly entire and flat. The 



