Ser. MelanospermevE. Fam. D}ctyotaceee. 



Plate LXXXII. 



DICTYOTA FASTIGIATA, Sond. 



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

 late, dichotomous or irregularly cleft. Fructification : spores super- 

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

 surfaces of the frond. — Dictyota [Lamx.), from Siktvov, a net; be- 

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

 appearance. 



Radix stuposa. Frons plana, linearis, membranacea, ecostata, areolata, dichoto- 

 ma aut vage divisa. Fruct. : sporcB superficiales in sores maculaformes ag- 

 gregate V. singulatim per utramque paginam frondis disperse. 



Dictyota fastigiata ; frond woolly at base, dark-brown, coriaceo-membra- 

 naceous, broadly Hnear, distantly forked ; axils rounded ; margin very 

 entire, slightly thickened; apices obtuse or minutely emarginate; 

 spores solitary, scattered ; tufts of paranemata on the same frond, re- 

 sembling sori. 

 D. fastigiata ; fronde basi stuposa badia coriaceo-membranacea lata lineari dis- 

 tanter dichotome partita ; axillis rotundatis ; margine integerrimo subincras- 

 sato ; apicibus obtusissimis v. minutissime emarginatis ; sporis solitariis sparsis; 

 paranematibus in maculas soriformes collectis in fronde ipsa cum sporis passim 

 evolutis. 

 Dictyota furcellata, Sond. PL Preiss. v. 2. p. 155. /. Ag. Sp. Alg. v. 1. p. 

 100. K-iitz. Sp. Jig. p. 556. Harv. Alg. Austr. Exsic. n. 71. 



Hab. Cast ashore from deep water. Western Australia, Preiss. Freman- 

 tle and Eottnest, common, W. H. H., G. Clifton. King George's 

 Sound and Cape Riche, IF. H. H. Flinders' Island, Br. Milligan. 



Geogr. Distr. Western and southern coasts of Australia. 



Descr. Root covered with rust-coloured, woolly fibres. Fronds tufted, 4-8-12 

 inches long, not less than a line, and seldom more than 2-3 lines in breadth, 

 preserving a nearly equal breadth throughout, covered with woolly hairs for 

 about \-\ inch above the base, thence upwards glabrous, repeatedly and 

 pretty regularly dichotomous. The forkings on large specimens are 1-2 

 inches apart, the axils are in all cases blunt, and the segments are erecto- 

 patent and tolerably fastigiate, the general outline being flabelliform. The 

 apices are often perfectly entire, as shown in our figure, but are .at least as 

 often minutely emarginate, the indentation only visible with a lens : as the 

 growth proceeds, the notch becomes a commencement of a new fork. The 

 fruit is but imperfectly known ; our numero\is specimens bear indifferently, 

 on the same fronds, either hemispherical, solitary spores ? {antheridia ?), or 

 roundish or oval clusters of paranemata similar to those that accompany 



