Botanical Society of Edinburgh. 203 



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 ex- 

 planation 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 

 likely 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 Xanthorrhoea 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 of the leaves of 

 this plant. 



July 12. — Dr. Balfour, President, in the Chair. 



The following papers were read : — 



1. " On Nostochinece," by John Ralfs, Esq. This paper comprised 

 descriptions of species of Sphcerozyga and Cylindrospermum, and will 

 appear in the ' Annals of Natural History ' and the Society's * Trans- 

 actions.' 



2. " On the Chemical Composition of the Fluid in the Ascidia of 

 Nepenthes," by Dr. A. Voelcker of Frankfort. (See p. 128.) 



Dr. Fleming called attention to the fact, that the young leaves of 

 barley distil a clear fluid from their extremities. He was not aware 

 of any analysis having been made of it. 



Dr. Balfour alluded to a similar phenomenon on the leaf of 

 Richardia (Calla) Mthiopica ; and Dr. Cleghorn made some remarks 

 on the acid secretion (oxalic acid) of Cicer arietinum, the chick pea, 

 which he had often observed the ryots collecting in India. 



3. "Notes of Excursions in the neighbourhood of Edinburgh," by 

 Dr. Balfour. In these notes Dr. Balfour gave a short account of the 

 botanical trips which he had taken with his pupils this season to 

 Dalmahoy, Arniston, Dysart, Prestonhall, Melrose, Gullane, Queens- 

 ferry and the Bass, and noticed some of the more interesting plants 

 which had been gathered. 



4. Dr. Balfour exhibited specimens of roots which had entered 

 and choked up tile -drains; viz. of an ash which had penetrated tile- 

 drains in Hampshire, filling them up completely for a great extent, 

 and causing serious injury, and stated that similar occurrences had 

 been observed in various parts of the country, more especially at 

 Muirkirk, the Carse of Gowrie and Prestonhall. The plants, whose 



