Ser. Rhodosperme^. Fain. Gelidiacea. 



Plate LXXIV. 



DICRANEMA REVOLUTUM, /. 4.. 



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

 duUarij stratum of slender, closely packed, longitudinal filaments ; 

 the intermediate of angular cells, smaller towards the circumference, 

 and the cortical of vertically seriated, minute, coloured cellules. 

 Fructification : 1, hemispherical conceptacles, containing within a 

 thick pericarp, 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. — 

 DiCRANEMA [Sond.), from StKpavov, aforlc, and vmia, a thread. 



Frons teretiuscula, dichotoma, stratis tribus eontexta. Stratum medidlare ex 

 Jitis lonrji.tudinalibus tenuibus densis ; intermedium celiulis rotundato-angidatis, 

 exterioribiis mlnoribus ; corticate cetlulis minimis coloratis vet'ticaliter seriatis. 

 Fruct. : 1, cijstocarpia liemisphm-ica intra pericarpiiim crassum sporas obovatas 

 pedicellatas ad placentam parietalem fibro-cellulosam foventia ; 3, tetrasporce 

 zonatim divisae, in apicibus tumidis (siHqiKeformibiis) ramoriim nididautes. 



DiCRANEMA revolutum ; frond (an inch long) setaceous, dichotomo-fasti- 

 giate ; axils widely spreading ; apices strongly revolute ; conceptacles 

 remote from the horn-like tip ; pod-like tips of tetraspores reflexed. 



D. revolutum ; fronde (unciati) setacea dichotomo-fastujiata ; axillis pateniissi- 

 mis ; apicibus revolutis ; conceptacidis ah apice rei)iotinsculis, apicibus siliquce- 

 formibus refiexis. 



DiCRANEMA revolutum, /. Ag. Sp. Alg. v. 2. p. 634. Harv. in Trans. H. I. 

 Acad. V. 22. p. 549 ; Alg. Austr. Exsic. n. 314. 



Sph^rococcus revolutus, Ag. Sp. p. 334. 



Hab. Shores of New Holland, Gandichaud. At Cape Riche, Western 

 Australia, W.E.H. 



Geogr. Distr. West and south coasts of Austraha. 



Descr. Root a minute disc. Fronds densely tufted, from an inch to 1-1 i 

 inches high, scarcely as thick as hog's-bristle, several times forked with 

 considerable regularity ; sometimes, from suppression of one of the forks, 

 irregularly cymose. All the divisions are remarkably patent, the branches 

 spreading often at right- or nearly right-angles. The tips of every segment 

 curl backwards into a hook. The conceptacles are borne near the ends of 

 the branches, at about the base of the hooked apex, which is prolonged 

 like a horn, at least thrice the diameter of the conceptacles. The pericarp 

 is formed from the intermediate and cortical layers of the frond ; the 

 placenta from the medullary. The latter adheres to one side of the peri- 



