82 FLORA ANTARCTICA. {Auckland and 



pallide flavo-brunnea, utrinque (chalaza apiceque) fusca, albumini appressa, exteriore remota ; inter has duas 

 raphe saepius solutus apparet. Albumen carnosum. Embryo parvus, albidus, oblique tetragonus, in basi albu- 

 minis immersus, hilo proximus. 



This species was, according to Lamarck, originally discovered by Commerson, who accompanied Bougain- 

 ville in his voyage to the Straits of Magalhaens, &c. I have gathered it abundantly both in Tierra del Fuego and 

 the Falkland Islands. In the latter locality it is very abundant, and had been previously detected by M. Gau- 

 dichaud and by Admiral D'Urville. It is rare in Campbell's Island, and was not observed upon Lord Auckland's 

 group. It is equally distinct from the R. grandiflora (Marsippospermum grandiflorum, Desv., Hook. Ic. Plant, 

 t. 533) and from the following, in the elongated bractea which subtends the flower, as well as the size of the 

 plant, form of the leaf and capsule, and curious structure of the seeds. I have no hesitation in retaining 

 Lamarck's specific name of Magellanica for this plant, the species being well characterized by that author, and 

 known to Desvaux at the time he established the genus Rostkovia ; this he did upon different grounds however 

 from those which induce me to retain it. 



M. Desvaux founds the genus on this solitary species, but grounds his generic character on an erroneous 

 idea of the structure of the capsule, which he describes (Journ. de Bot. 1. c.) as " capsula globosa, uniloculars, 

 non dehiscens ; trophospermum suturale " (p. 326) ; and again in the previous page, " Je crois que la capsule ne 

 s'ouvre point; par suite d'une observation generale, e'est que tout fruit qui n est point anguleux dans aucune de 



ses parties, n est pas dehiscent, surtout s'il est sph&rique les graines en grand nombre sont disposees sur 



trois trophospermes (placentae) fixes sur les parois de la capsule et alternant avec les indices de dehiscence qui 

 s'aper^oivent au milieu des parois des loges, et qui sont toujours indiques, malgre que cette dehiscence n'ait 

 point lieu dans quelques genres de la famille des Joncinees" (p. 325). The capsule of R . Magellanica I have 

 described as of a very hard consistence, and its dehiscence does not take place until a considerable period after 

 the apparent ripening of the seeds ; that it does burst is however abundantly evident, and the dehiscence takes 

 place by three valves, exactly as in Desvaux's genus Marsippospermum and in other Juncece, the placentae occupy- 

 ing the axis of the valves. From the above extract I conclude that M. Desvaux did not examine fully ripe cap- 

 sules, and took the groove at the back of the valves, which is seen in almost all Junci, denoting the position of 

 the placenta, for the line of dehiscence. In the work alluded to no description of the seeds themselves is given, 

 though another genus is founded on a supposed peculiarity of structure in that organ. Mr. Brown (Piodr. 

 p. 258), in his observations on the genus Juncus, remarks that no dependence is to be placed on the form of the 

 testa as a generic character, " nee secernendae eae seminibus scobiformibus, testa nempe, quae in pluribus 

 utrinque laxa, in his valde elongata ;" and as in the genus Juncus itself there are several forms of that organ, 

 so in Rostkovia, as it now stands, it differs remarkably in two of the species. In R. grandiflora the outer inte- 

 gument of the seed is lax and drawn out at both ends, as in Juncus castaneus, Sm., and several other species ; 

 but in the R. Magellanica it assumes a form which I have not seen in any other species of the Natural Order, 

 forming a very thick, even seed-coat, hard, smooth and shining externally, marked on one side with a pro- 

 minent ridge, indicating the position of the raphe ; within it is soft and spongy, with a large cavity. Inside this 

 the nucleus hangs loose, suspended by the vessels of the raphe, which are more or less detached and often quite 

 separate from the walls of the seed-coat, except at the base. The inner membrane immediately surrounds the 

 albumen ; it is thin and membranous, obscurely striated or reticulated, of a pale brown colour with a broad orbi- 

 cular dark-coloured chalaza at the summit and another dark spot and apiculus at the pendent apex. This mem- 

 brane is quite free from the outer, and analogous to what is generally considered as the testa in many Junci 

 which are described as not having that organ scobiform, but in which the true outer membrane of the seed, ana- 

 logous to the coriaceous one of the present species, is delicate and hyaline, either altogether deciduous or leaving 

 a few filamentous residua round the base and apex of the seed, or as in J. scheuchzerioides, leaving the raphe 

 as the only attachment between the seed and placenta. In some species of the Order this outer membrane forms 

 with water a transparent jelly, in which the seed appears immersed ; it is very similar to what is seen surround- 



