Miscellaneous, . 183 



2nd. When the electrodes are brought into contact, one with the 

 external surface of the spongioles of a plant, and the other with the 

 sap ascending from the root, the sap and the external surface are in 

 opposite electric states. The effects which are here observed with 

 the galvanometer may, in the majority of instances, be due to ordinary 

 electro-chemical actions ; but in some instances the effect cannot be 

 referred to these actions, but may be referred to the organic changes 

 which occur in the roots during vegetation. 



3rd. That with the petals of flowers slight currents were obtained ; 

 and, 



4th. In fruits and tubers powerful currents may be occasionally 

 obtained ; but these effects are evidently secondary results, due to the 

 reaction of the different vegetable juices upon each other. 



4. "Notice of some iVdditions to the Ilepaticse of the neighbour- 

 hood of Edinburgh," by John Lowe, Esq. 



5. "Record of Localities for Rare Plants," by Prof. Balfour. 



6. "Continuation of Account of some of the Contents of the 

 Museum at the Botanic Garden," by Prof. Balfour. 



7. " List of the Fibrous Plants of India," communicated by Prof. 

 Balfour. 



MISCELLANEOUS. 



On the probable Origin of the Organized Beings now living in the 

 Azores^ Madeira^ and the Canaries. By M. Oswald Heer. 

 In a letter to M. A. DeCandolle. 



In your Geography of Plants you have adopted the opinion of 

 Edward Forbes, that in the miocene period the European continent ex- 

 tended to the Azores and Canaries, and supported it by fresh proofs*. 

 In fact, the predominant European character of these islands, which 

 occurs in their insects as Avell as in their flora, proves that they were 

 anciently joined to the continent. Nevertheless we must not forget 

 that, as compared with Europe, these islands are very different from 

 those of the Mediterranean, They are distinguished in the first 

 place by a much greater number of peculiar species, which constitute 

 a third or a fifth of the plants ; and in the second by some American 

 types, which make their appearance in all these islands. These are 

 not only certain American species which might have reached them 

 accidentally by the agency of the winds and currents, or of man, but 

 American genera which are represented by peculiar species. I will 

 instance the genera Clethra, Bystropogon, and Cedronella^ as also 

 the unique pine of the Canaries {Finns canariensisy Sm.), which 

 belongs to the American forms with acicular ternate leaves. The 

 relations of the Laurels is very remarkable in this respect ; they form 

 a great part of the forests of Madeira and the Canaries, dividing into 

 four species and playing an important part. Two species (Oreo- 



* DeCandolle, Ge'ographie Botanique raisonnee, p. 1310. 



