^9Q French National Instiiuie. 



plant of the family of Palm-trees, of which be has made a 

 genus under the name oF ptijckosperma, and placed it next 

 the elati and arccas. This plant was discovered by the 

 author in New Ireland : it rises frequently to the height of 

 do feet and upwards, and yet its trunk is only two or three 

 inches in diameter. These proportions induced him to give 

 it the name of gracilis. It is astonishing, as M. Labillar- 

 diere remarks, that so slender a tree can support itself; but 

 we know that in all the monocotyledons, the hardest of 

 the ligneous part is external, and this structure ^\ives to the 

 plants of this class a strength which those cannot possess 

 whose most solid fibres are in the centre. 



M. Lamouroux has presented to the Class a very exten- 

 sive work on marine plants. Little or no attention has 

 been paid to these singular vegetables, and tho.y have been 

 arranged in rather an awkward manner: M, Lamouroux, 

 by forming into a single group all the plants known to ex- 

 ist in the sea, sd^enni to have wrought an advantageous 

 change. 



The little progress which had been made in the study of 

 the algae, was the cause of the disagreement among bota- 

 nists as to the organs which serve to the reproduction of these 

 Cryptogamia. M. Correa, in a work written expressly on 

 this subject, had recognised male and female organs in the 

 tubercles placed at the extremities of the ramifications of 

 these plants. M. Ivamouroux partakes of this opinion ;but 

 he characterizes with precision the different parts ef these 

 organs, and thus throws a great deal of clearness on the 

 gtudy of these singular vegetables. This author has besides 

 observed that the kind of algae which grow on granite, are 

 never the same with those found on calcareous stone or on 

 sand, and vice versa. As to their interna) organization, M. 

 Decandolle had ascertained that it was devoidof vessels, and 

 entirely fornied of cellular texture. M. Lamouroux di- 

 stinguishes tvvo kinds of cellules ; thp one being long hexa- 

 gons, which form the stalks and the nervous parts (ncr- 

 pures) of the ramifications; the other kind is of the same 

 form with the foregoing, hut has sides almost equal, and 

 which constitute the membranous or Ibliaceous substance. 



M. Lam()urt)ux thinks that the foriner niay be analogous 

 to the vessels, and the second to the uiricular texture oi 

 the most perfect vegetables. Tnese general labours led the 

 author to form in this family several new genera, which he 

 jias also presented to the Class for their approval. 



M. Mirbcl has continued his researches on vegetable phy- 



giologv. Formerly it hud been ascertained that the albumen 



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