18G Miscellanea. 



Remarks on the Origin of Plants, and the Physical and 

 Geographical Distribution of Species. By the Rev. Dr. 



Fleming. 



[Botanical Society of Edinburgh, June 14, 1849.] 



The author stated that it had been assumed as a first principle, 

 connected with an extensive series of speculations in botany and 

 geology, that species had sprung from single centres, and that the 

 individuals had " radiated from one point to greater or lesser distances 

 around it," according to Dr. J. Hooker; or that all the individuals 

 of a species could be traced " from a single progenitor, or from two, 

 according as the sexes might be united or distinct;" and hence the 

 origin of the phrase, " specific centres." In opposition to this view, 

 it was stated that the history of the human race, traced to their 

 origin in a single pair, did not lurnish an analogical argument of 

 any value ; while the dependence of the carnivorous animals on the 

 herbivorous kinds, and the latter, along with man himself, on plants, 

 gave good grounds to conclude that mam/ individuals, of grasses for 

 example, were requisite in the first instance, and were brought forth 

 abundantly. These considerations rendered the assumption of "spe- 

 cific centres" extremely improbable; but the occurrence of similar 

 species, in localities remote from one another, and even in opposite 

 hemispheres, over which, by no conceivable process, could dispersion 

 from a single plant be reconciled with the phenomena, did, in the 

 opinion of the author, furnish a demonstration of its absurdity. Dr. 

 Hooker, while admitting the identity of the species of opposite hemi- 

 spheres, acknowledging about thirty antarctic forms as identical with 

 European plants, even after careful comparison and with the ablest 

 coadjutors, is inclined to consider the identity, not as indicating a 

 multitude of progenitors of a species, but as an anomaly, the expla- 

 nation of which must be sought for " in some natural cause." 

 Professor E. Forbes disposes of the anomaly in a more summary 

 manner, by an assertion, that "species of opposite hemispheres, 

 placed under similar conditions, are representative, not identical." 

 If this opinion be correct, then form and structure are vastly inferior 

 in value, in the determination of species, to latitude, a conclusion not 

 Ikely to be adopted. The author concluded by recommending the 

 abolition of the term " specific centres of distribution," as involving 

 an erroneous hypothesis, and the substitution of the phrase '■^patches 

 of distribution." 



Dr. Fleming exhibited a specimen of Xanthorrhcea hastilis, which 

 had been sent by Assistant-Commissary Neill from St. George's 

 Sound, together with some implements manufactured by the abori- 

 gines, by means of the gum exuded from the bases ol the leaves of 

 this plant. 



