Ser. RnoDOSPERMEiE. Fam. Gelidiacea. 



Plate CXX. 



DICRANEMA GREVILLEI, Sond. 



Gen. Char. Frond terete, dichotomous, formed of three strata ; the me- 

 didlary stratum of slender, closely packed, longitudinal filaments ; the 

 intermediate of angular cells, smaller toward the circumference ; the 

 cortical of vertically seriated, minute, coloured cellules. 'Fructifica- 

 tion : 1, hemispherical conceptacles, containing, within a thick peri- 

 carp, pedicellate, obovate spores, attached to a parietal fibro-cellular 

 placenta (formed from the medullary stratum) ; 2, zonate tetraspores, 

 lodged in the swollen (pod-like) tips of the branches. — Dickanema 

 [Sand.), from BtKpavov, a forh, and V7]\xa, a thread. 



FroHS teretiuscula, dichotoma, stratis trlbiis contexta. Stratum medullare ex 

 fills longitudlnalibus tenidhiis densis ; intermedium celluUs rotundato-angu- 

 latis, exterioribus minoribus ; corticate cellidis minimis coloratis verticaliter 

 seriatis. Fruct. : 1, cijstocarpia hemisphcerica, intra pericarpiuni crassum 

 sporas obovatas pedicellatas ad placentam parietalem fibro-cellidosam foventia ; 

 2, tetrasporcB zonatim dlvisa, in apicibus tumidis fsiliquceformibusj ramorum 

 nidulantes. 



DiCRANEMA Grevillei ; frond (3-4 inches long) ultra-setaceous, dicho- 

 tomo-fastigiate ; axils widely spreading ; apices patent or divaricate ; 

 conceptacles near the obtusely horn-like tip ; pod-like tips (of tetra- 

 spores) erecto-patent. 



D. Gxt\\\\&\ ; fronde (S-4f-pollicari) zdtra-setacea dicJiotomo-fastigiata ; axillis 

 patentibus ; apicibus patentibus v. divaricatis ; conceptaculis ab apice obtuso 

 parum remotis ; apicibus siliquaeformibus tetrasporarmn erecto-patentibus. 



Dickanema Grevillei, Sond. in Bat. Zeit. 1845, p. 56. Ft. Preiss. v. 3. p. 173. 

 /. Ag. Sp. Alg. v. 2. p. 634. Harv. Alg. Austr. Fxsic. n. 315. 



Gracilakia pumila, Grev. Fd. Journ. Nat. Sc. v. 3. p. 338, cum icone. 



Cystoclonium ? pumilum, Kiitz. Sp. Alg. p. 757. 



Hab. Australia, Kerl. Greville. West Australia, Freiss. Abundant on 

 Cymodocea antarctica, etc., near Fremantle, and at King George^s 

 Sound, W. H. H., G. Clifton, etc. South Australia, Dr. Curdie. 

 Flinders Island, Dr. Milligan. 



Geogr. Distr. West and south coasts of Australia. 



Dbscr. Root a minute disc. Fronds densely tufted, 2-4 inches long, thicker 

 than hog's-bristle, many times forked, fastigiate, forming nearly globular 

 tufts. The branching is very regular and uniform, merely varying from 

 the occasional non-development of one of the arms of the fork ; the axils 



