Ser. Melanosperme^,. Fam. Fucncea;. 



Plate CXLV. 



SARGASSUM DECURRENS, Ag. 



Gen. Char. Root scutate, i^yow^/ piiinately decompound, with distinct stem, 

 branches, leaves, vesicles, and receptacles. Vesicles stipitate, supra- 

 axillary, simple, most frequently mucronate or leaf-bearing. Recep- 

 tacles pod-like, torulose or moniliform, axillary. Scaphidia dioicious. 

 Spores obovoid. — Sargassum [Ag.), from the Spanish sargazo, a name 

 given by navigators to floating seaweed. 



Radix Hcutata. Frons pimiatim decomposita, cuide propria, rmnis, foUis, vesi- 

 culis, receptacidisque donata. Vesiculce stipitatce, supra-axillares, simplices, 

 sapissime wucronaice v. foliiferee. Beceptacnla sdiquceforrnia, torulosa v. 

 nodtdosa, axdlaria. Scophidia dioica. Spotre obovoidea. 



Sargassum ^/^ewn-cw^ ; frond flat, foliaceous, ribbed, distichously pinnate; 

 piniife pinnatifid, their segments linear, entire, ribbed, taper-pointed ; 

 vesicles numerous (on the fertile branches), spherical, pointless ; recep- 

 tacles cylindrical, unarmed, in a panicle equalling the pinna; each 

 branchlet subtended by a linear floral leaf. 



S. decurrens ; fronde plana foUacea costata disticJie pinnata ; pimiis pinnati/idis ; 

 laciniis linearibns integerrimis costatis apice acmnnatis ; vesicuUs numerosis 

 sphairicis mnticis ; receptacnlis cylindraceis, inermibiis, in panicidam folium 

 cequantem, difipositis ; pedicellis folio Jlorali linear if idcratis. 



Sargassum decurrens, Ag. Sp.p. 42 ; Syst. 308. J. Ag. Sp. Jig. v. l.p. 285. 

 Harv. Alg. Austr. Exsic. n. 11. 



Pterocaulon decurrens, Kiifz. Sp. Alg. p. 606; F/igc. Gen. p. 360. 



Fucus decurrens, R. Br. MS. in Turn. Hist. t. 194. 



IIab. North shores of New Holland, R. Brotvn. Torres Straits, Herb. 

 Aresch. [fideJ.Ag.). Australm, Miss Atme Taylor. Eottnest Island, 



r. H. H. 



Geogr. Distr. Northern and western coasts of Austraha. 



Descr. Root discoid. Fronds rising with a short, compressed or winged stem, 

 which divides near the base into several branches. Branches 12-15 inches 

 long, or perhaps more, flat and leafy, traversed by a strong midrib, linear, 

 naked below, but from the middle to the extremity closely and distichously 

 pinnated. Pinna flat, and midribbed like the primary branch, patent, pin- 

 natifid at or near the extremity ; the ultimate lacinise narrow and taper- 

 pointed. In young specimens the branch is i inch wide, the pinnte 4—5 

 lines, the pinnules 1-2 lines wide; in the older frond the laciniaj are much 

 narrower and more attenuate. Vesicles are only found on the inflorescence ; 

 they are globose, pointless, 2-2J- lines in diameter, on very short stalks. 



