Ser. Melaxosperme.'E. Fam. Dictyotacea. 



Plate CXIX. 

 DICTYOTA RADICANS, Harv. 



Gen. Char. Root woolly. Frond flat, linear, membranous, ribless, areo- 

 late, dichotomous or irregularly cleft. Fnictificat'ion : spores super- 

 ficial, either collected in spot-like sori or scattered singly over both 

 surfaces of the frond. — Dictyota {Lamour.), from Scktuov, a net ; 

 because the surface, under a lens, has a netted or, rather, a tessellated 

 appearance. 



Radix stuposa. Frons plana, linearis, membranacea, ecostata, areolata, dicliotoma 

 aut vagejiasa. Fruct. : spores superficiales, in soros maculceformes aggregata 

 V. singulatiin per utramque paginam frondis dispersce. 



Dictyota radlcans ; frond not woolly at base, stipitate, rooting by scat- 

 tered thread-like fibres issuing from the stipes and lamina, dichotomo- 

 pinnatifid; segments cuneate, the lateral erect, with narrow sinuses; 

 apices very obtuse ; sori scattered, confined to the middle part of the 

 frond. 



D. YSLdicans ■,froude estuposa stipitata, basijibris crassis sparsis e stipite et lamina 

 einissis radicaute dichotomo-pinnatijida ; segvientis cuneatis, lateralibiis erectis ; 

 sinubus avgustis, apicibus obtusissimis ; soris ejf'usis, in medio parte frondis 

 collectis. 



Dictyota radicans, Harv. in Trans. R. I. Acad. v. 22. p. 536; Alg. Austr. 

 Fxsic. n. 69. 



Hab. At Rottnest and Garden Islands, near Fremantle, W.H.H. 



Geogr. Distr. West Austraha. 



Descr. Root consisting of many, long, simple, thread-like fibres, proceeding 

 partly from the base of the frond, and partly from the lower parts of the 

 principal rachides ; the fibres as thick as hog's-bristles, and from 1 to 

 3 inches long. Frond irregularly dichotomous, the segments linear, cu- 

 neate, much attenuated at base, repeatedly forked, occasionally sub-alter- 

 nately decompound, 1^-3 lines wide, quite entire, erecto-patent, with blunt 

 axils and tips. The areoles of the membrane are oblong, 3-4 times longer 

 than broad ; the superficial cellules minute and quadrate. Membrane rather 

 translucent. The colour is a i)rovvnish-olive, paler toward the extremities. 

 The substance is membranaceous, and the frond, when not too old, adheres 

 moderately to paper in drying. 



This species, which much resembles some forms of J). dicJio- 



