Ser. CiiLoitosPEiiMEJE. Fam. Valoniacea. 



Plate XXXII. 



STRUVEA PLUMOSA, Send. 



Gen. Char. Frond stipitate, flabelliform. Stipes rooting, unicellular and 

 monosiphonous, transversely rugulose, thinly coated with calcareous 

 matter, at maturity crowned with an oblong, midribbed, open net- 

 work, composed of anastomosing, pinnately decompound, articulated, 

 confervoid filaments. Endochrome bright-green, thin and watery. — 

 Struvea (Sond.), in honour of H. de Struve, Ambassador from 

 K-ussia to the Hanseatic Towns, and a patron of Natural History. 



Frons stipitata, flabelliformis. Stipes radicatus, monosiphonius, conlinuus, annu- 

 latim constrlctus et transversim rvgidosus, epldermlde tenia calcarea donatus, 

 in cetate inajorl retlculo flabelliformi oblongo costato coronatus. Reticulum 

 ex fills confervoideis articulatis distiche pinnatis anastomosanlibus evolutum. 

 Slice us aquosus, viridis. 



Struvea plumosa ; network (1-2 inches long) oblong-oval, crenate, its 

 filaments 2-3 times pinnated ; articulations of the pinnee twice or 

 thrice, of the pinnules once and half as long as broad. 



S. plumosa; flabello oblongo-ovall (\-2 uncias longo) crenato, fills anastomo- 

 santlbus 2-S-plnnatls ; articulis pinnarum dlametro 2-3-plo, pinnularum 

 sesqui-longiorlbus. 



Struvea plumosa, Sond. PI. Preiss. v. 2. p. 151. Harv. in Trans. R. I. 

 Acad. v. 22. p. 564. 



Hab. On reefs, at low-water mark. Western Australia : at Garden Is- 

 land, Preiss ; Eottnest, W. H. H., G. Clifton. 



Geogr. Distr. As above. 



Descr. Root much branched, fibrous, matted. Fronds densely tufted. In an 

 early stage the plant consists of a single, lineari-clavate, very obtuse cell, 

 transversely corrugated in its lower half, smooth above, composed of a hya- 

 line membrane, and filled with bright-green, watery endochrome. At this 

 stage it is 1-H inches high, and it grows to nearly two inches in length 

 before undergoing change. At length the apex lengthens, and becomes 

 attenuated to a slender point, and corrugated like the lower half, and then 

 a new cell is formed at the summit of what must now be called the stipes. 

 This apical cell is the commencement of the network, or basal cell of the 

 rachis or midrib. From it are developed a series of cells, one above the 

 other, to the number of ten or twelve, and each of these emits from its 

 shoulders a pair of opposite pinna?, which are at first free and pectinate ; 

 but afterwards, becoming once and again pinnulate, their pinnuke anasto- 

 mose, and form the network of the fully developed frond. Specimens of 



