Academy of Sciences in Paris. 359 



Among the Euphorbia (Enphorbiacees) of Chili, M, de Jussicu 

 remarks particularly the Croton lanceolatum of Cavanillas, in which 

 lie finds the type of a new genus, to which he has given the name of 

 Chiropetalum, expressive of the peculiarity of its petals being di- 

 vided into palmated straps. This genus, and those analogous to 

 it, form a very natural little group in the tribe, remarkable for the 

 colouring principle which is peculiar to them. The author also adds 

 a new species to the genus Colliguaya, but considers it as scarcely 

 varying from the Exceecaria. He then describes a new kindred 

 genus, which he calls Adenopairis, and thence takes occasion to 

 offer some remarks on the groups of Hippomanice and Euphorbice, 

 which he proposes to unite into one, in which case this section, or 

 tribe, of the order of the Euphorbice (Euphorbiacees) would be dis- 

 tinguishable by the almost constant existence of a milky sap {sue 

 laiteux), and by the extreme simplicity of the organs of fructifica- 

 tion, which renders it necessary to have recourse to the original dis- 

 position (inflorescence) in order to find the generic characters. The 

 memoir terminates with a list of the genera now admitted by the 

 author in this tribe, which is too long for insertion, particularly as 

 we have mentioned all the new ones suggested by M. de Jussieu. 

 The report concluded by recommending the memoir to the appro- 

 bation of the Academy. 



Ligneous Fibres. On the 19th September, Messrs. Mirbel, Des- 

 fontaines and Cassini, made the following report on a work by M. 

 Paiteau, entitled * Me'moires tendant a faire admettre au nombre 

 des v^rites ddmontre'es la theorie de La Hire, touchant 1'origine et la 

 direction des fibres ligneux dans les ve*getaux.' In the memoirs of 

 the Academy for the year 1708,La Hire maintained that the ligneous 

 layers which occasion the increase of bulk in trees have a direction 

 from top to bottom ; that they proceed from the buds, of which they 

 are the roots ; and that, like other roots, they have a tendency to 

 bury themselves in the earth. In fact the annual beds of the trunk 

 have one end attached to the branches springing from the buds, and 

 the other to the roots concealed in the earth, forming between these 

 parts a necessary connecting link which cannot be broken without 

 injuring both the buds and the roots. La Hire's idea, however, 

 went much further ; he imagined that each bud produces roots, which 

 form with the roots of the other buds a sort of case between the 

 old wood and the bark : this case, which is merely the annual bed, 

 descends gradually from the top of the highest trees down to below 

 the surface of the earth, where all the roots separate, and assume the 

 form in which we find them. "When this hypothesis is admitted, it 

 is easy to explain how a swelling is formed at the upper part 

 from a wound or ligature on the trunk of a tree ; the roots of the 

 buds, not being able to pass beyond that spot, collect into a mass, 

 and strengthen and thicken instead of elongating. Then one of 

 two things happen either the swelling becomes sufficiently deve- 



VoL.II. Nov. 1831. 2B 



