

. 



Dr. Hookefs Flora Antarctica. \ J?, 



there are no traces of medullary rays. We conclude this subject 

 with the observation, that the periodical increment of the trunk 

 being dependent on, or coincident with, the formation of the 

 laminae, these appear to perform the office of the leaves in the 

 higher order of plants ; and that the Lessonia is also in this re- 

 spect analogous to an Exogenous plant, deprived of its woody 

 tissue, for it is a stem composed of layer upon layer of cellular 

 tissue, deposited round an axis, which, like the pith, when once 

 formed, is afterwards but slightly modified." 



The ten described species of the gigantic Macrosystis, Dr. 

 Hooker's own observations have enabled him to reduce to one ; 

 remarking that few botanists in Europe have ever seen even a 

 tolerable suite of specimens from one single plant of this Alga, 

 such as give a fair idea of the differences between the various 

 leaves and bladders along some 300 feet of stem, with the sub- 

 merged fructifying fronds from the root. The general interest of 

 the following account must be our apology, if one is needed, for 

 so lengthened a series of extracts. 



" It is seldom that the history of an Alga is likely to afford inter- 

 est or amusement to the general reader, unless it be a positively 

 valuable plant in an economic point of view. Like the Sar- 

 gasso-weed of the Tropics, however, the Macrosystis is so con- 

 spicuous, and from its wandering habits, often occurs so unex- 

 pectedly, that the attention of our earliest voyagers has been di- 

 rected to it, and we are consequently led back by our enquiries 

 ^to its first discovery, to the annals of those perils and privations 

 which have ever marked the progress of discovery and enterprise 

 in the stormy seas of the south. 'Nihil vilior Alga,' is a saying 



j more trite than true, and one which a seaman can never use ; for 



these weeds often prove his unerring guide towards land, as they 

 surely are to the direction of the currents; or become of more 



I importance still in the case of the present plant ; for it is, where 



growing, not only the infallible sign of sunken rocks, but every 

 rock that can prove dangerous to a ship is conspicuously buoyed 

 by its slender stem and green fronds, and we may safely affirm 

 that without its presence many channels would be impracticable, 

 and numerous harbors in the south closed to our adventurous 

 mariners. 



" The first notice of the Macrosystis, with which we are ac- 

 ■ quainted, is of so early a date as the middle of the 16th century, 

 W and occurs in a copy of sailing directions for mariners, with the 

 title ■ A Ruttier from the river of Plate to the Streight of Majelana,' 

 a nd forms part of < A special note concerning the currents of the 

 sea between the Cape of Buena Esperanza and the coast of Bra- 

 silia, given by a French pilot before Sir John Yorke, Knt., be- 

 fore Sebastian Cabote, which pilot had frequented the shores of 

 Brazilia eighteen voyages/ (Hakluyt, ed. 2, vol. iv, p, 219). 



