SClErtlFIC NEWS. 159 



support itself: but we know, that all the monocotyledonous 



plants have the liardest part of their wood externally ; and ; ^^ ♦^^•t 



this structure imparts to them a degree of strength, which 



they could not possess if their most solid fibres were in the 



centre. 



Mr. Lamouroux has presented to the class a very exten- Marin« plants* 

 sive work on marine plants. In forming one group of all 

 these Mr. L.'has made a useful innovation. The little pro- 

 gress that has been made in the study of seaweeds has pre- 

 vented botanists from being agreed respecting the organs 

 of fructification. Mr. L. not only embraces the opinion of 

 the male and female organs being placed in tubercles at 

 the extremity of their ramifications, but characterises the 

 different parts of these organs with precision. He has far- 

 ther observed, that the species growing on granite, on lime- 

 stone, and on sand, are always different. As to their inte- 

 rior organization, Mr. DecandoUe had observed, that it was 

 destitute of vessels, and entirely formed of cellular texture. 

 Mr. L. distinguishes two sorts of cells; one very long, and 

 hexagonal, forming the stalks, and the ribs of the ramifica- 

 tions ; the other also hexagons, but nearly equal sided, 

 and constituting the membranous or foliaceous substance. 

 The former he supposes are analogous to the vessels, and 

 the latter to the cellular texture of the more perfect vege- 

 tables. His researches have also led him to form several 

 new genera. 



To CORRESPONDENTS. 



On perusing Dr. Davy's paper in our present number, 

 and the letter from Mr. J. Davy, in which he mentions the 

 properties of Dr. Davy's zuthic acid, or compound of oxi- 

 muriatic gas and oxigen, p. 43 of our last number, J. M. 

 will probably perceive, that the objects of his obliging com- 

 munication are there answered. 



To some other correspondents a similar remark will ap- 

 ply. 



.AfET£OROLOGICAL 



