Dr. Greville on some new species of Sargassum. 217 



The only specimen — and it is a mere fragment — which I have 

 seen of this Alga was disentangled from some other species. 

 There appears to be a disposition in the leaves towards the ends 

 of the branches to become incurved, but this may not be a per- 

 manent character. 



14. Sargassum Wightii (nob.) ; caule compresso, distiche ramose ; 

 foliis anguste lanceolatis, integerrimis ; vesiculis ellipticis, apicu- 

 latis, longe petiolatis, petiolis planis, dilatatis ; receptaculis linea- 

 ribus, compressis, ramosissimis, in racemo amplo subtruncato 

 aggregatis. 



Wight in herb. no. 12 & 13. 



Hab. in mari Peninsulae Indise Orientalis ; Wight. 



Root an expanded disc, throwing up several mostly undivided 

 stems from 1 to 2 feet in length, or probably more, giving off 

 branches in a distichous manner, at intervals of half an inch or 

 more; the lower ones are several inches long, becoming gra- 

 dually shorter, and more remote as they approach the summit : 

 the fruit-bearing ramuli are very short, and, like the rest, di- 

 stichously arranged. Leaves from 1 to near 2 inches in length, 

 narrow-lanceolate, sometimes almost linear-lanceolate, nearly 

 equally attenuated at each extremity, acute, quite entire or 

 obscurely repando-dentate, furnished with a somewhat faint nerve 

 and a few scattered pores. Vesicles about the size of the seed 

 of Lathyrus odoratuSj elliptical, apiculate, on long dilated folia- 

 ceous stalks, in young plants arising from the axils of the cau- 

 line leaves ; afterwards accompanying the fructification but spa- 

 ringly, and generally taking the place of a leaf. Receptacles 

 axillary, filiform, compressed, very much divided, the exterior 

 branches the longest, so that the racemes have a cymose or tassel- 

 like appearance. The racemes vary much in size, being dense, and 

 not more than 2 or 3 lines long in some plants ; in others half 

 an inch and much more lax. Colour dark, olivaceous, the recep- 

 tacles black when dry. Substance slightly cartilaginous. 



In some specimens, the branches, besides producing axillary 

 racemes, have the appearance of terminating in a larger raceme, 

 an effect which seems to be produced by the ultimate leaves being 

 converted into receptacles, the whole preserving the truncate and 

 tassel-like outline of the axillary racemes. 



Eor this fine and very striking Alga I have reserved the name 

 of the excellent and indefatigable naturalist from whom I received 

 it. It is quite unlike any other species with which I am ac- 

 quainted. 



15. Sargassum cervicorne (nob.) ; caule compresso, distiche ramoso ; 

 foliis late lineari-lanceolatis subintegerrimis, superioribus atque in 

 ramis fertilibus brevioribus, lanceolatis, plus minusve dentatis ; 



