IS 14.] Imperial Institute. 453 



capsules, placed sometimes within, sometimes below the former, 

 and containing only small, round, transparent grains, larger than 

 those which constitute the yellow powder; but these particular 

 capsules have not been found in more than one-third of the species 

 of lycopodiuins, and vain attempts have been made to discover 

 them in the remainder. 



M. Desvaux agrees nearly with M. de Beauvois as to the facts, 

 but disputes the consequences drawn from them. He sees in the 

 yellow powder nothing but bulbs and buds, or as he calls them 

 propagula, which do not stand in need of fecundation in order to 

 germinate. The other grains observed by M. de Beauvois, to judge 

 from their small number, their transparence, and their varied and 

 irregular figure, are merely abortive propagula. 



^ M. de Beauvois replies by showing that all the definitions of seeds 

 given by the most skilful botanists are applicable to these globules ; 

 and setting out from the principle that the existence of seeds 

 supposes that of a female gender, and that the existence of one sex 

 supposes the other, he maintains his original opinions. 



His adversary replies that a nominal definition formed from 

 received ideas cannot decide a dispute in which these very ideas are 

 called in question, and that the visible characters of structure 

 observed in all seeds are far from being verified here on account of 

 the smallness of the object. 



We see that the discussion begins to become metaphysical. The 

 only mode of deciding the point would be to produce the fecunda- 

 tion of what is considered as the pistil by means of what is consi- 

 dered as the pollen. But who could flatter himself with being able 

 to make upon organs so delicate an experiment, which has so fully 

 demonstrated the existence of sexes in ordinary plants. 



M. Desvaux has given likewise a methodical distribution of all 

 the known lycopodiums, adding some subdivisions to those esta- 

 blished by M. de Beauvois in a preceding memoir on the same 

 family, and taking for his principal basis the existence of two sorts 

 of capsules, and the division of the capsules into cells more or less 

 numerous. 



M. de Candolle, Correspondent of the Class, and Professor at 

 Montpellier, has made us acquainted with parasite mushrooms of a 

 new kind, which he names rkimctones, or death of the roots, be- 

 cause they attach themselves to the roots of plants, and occasion 

 their rapid death. M. Persoon had united under the name of 

 tclerotium the mushrooms which are fleshy internally, like the 

 truffle, but destitute of those veins which give a marbled appearance 

 to the flesh of the truille. Hedwig had separated from them the 

 erisiphes, which live on the surface of leaves; but in those which 

 remain there are still a sufficient number of characters to constitute 

 two genera; one genus, which is not essentially parasite, ami 

 grows in dung and putrefying plants, DM neither fibres nor roots ai 

 u'iace ; the other (constituting the rfuxoctmes) emits simple 



