69 



cultivated condition, that the Asturian districts were the lowest in ge- 

 neral cultivation among districts of equal extent. 



Although annuals and the class of weeds generally accompanying 

 crops are at first favoured by culture, which opens the soil for their pro- 

 pagation, it seems that the tranquil development of perennial wild 

 Plants takes place most completely where culture is imperfect, or en- 

 tirely suspended : whence it follows, that, if any perennial wild Plants 

 suited by their habits to the Asturian district happened to be introduced 

 into them, their chance of existing and spreading would be greater than in 

 other districts of Ireland. In addition to the evidence furnished by the re- 

 tarns of the Registrar-General, the author referred to the writings of 

 Arthur Young, and to the Agricultural Surveys of the Counties of Ireland, 

 in order to show that the same relative condition of the Asturian districts 

 with reference to cultivation had been in existence as long as the sub- 

 ject had attracted any notice. It was shown by numerous references, 

 that a great many well-authenticated instances of the introduction of 

 Plants through commercial and general intercourse have greatly 

 changed the Mora of different countries. These changes were often ef- 

 fected within a comparatively short period of time, and they were more 

 or less complete in proportion to the more or less favourableness of the 

 climatic condition of the new stations of the introduced Plants. After 

 fully discussing these results, the author puts forward his views in the 

 following propositions : — 



During two periods of prolonged and intimate intercourse between 

 the northern coast of Spain and the whole of Ireland, the conditions for 

 bringing the seeds of various Plants into the latter country from the former 

 probably existed ; and during the more recent of these periods, the exist- 

 ence of such trading and fishing intercourse between Spain and the Astu- 

 rian districts of Ireland is so well established, and was of such a kind as to 

 render the introduction of accidental seeds almost certain. Such seeds 

 as required a warmer climate than that of Ireland for their germination 

 necessarily failed, while those which were suited to the physical condi- 

 tions into which they were thrown became naturalized. The winter 

 isothermals, and the corresponding distribution of minimum temperature, 

 confined the range of these Plants to the two narrow littoral districts where 

 they are found. The cold and wet summers which often exist in Ire- 

 land would speedily destroy such annuals as happened to be introduced 

 from the warmer summer climate of the North of Spain ; but a few of 

 the perennials might still continue to exist, owing to the favourable con- 

 ditions of winter temperature in the West of Ireland. 



The author briefly discussed the grounds which we possess for be- 

 lieving in a former intercourse between Spain and Ireland at a very re- 

 mote epoch ; and he examines, with great minuteness and detail, the 

 evidence of such intercourse during a more modern period. It appears 

 that from the thirteenth to the sixteenth centuries, inclusive, the West 

 and South- West of Ireland were in close communication with the ports 

 of Biscay and the Asturias. Local histories and traditions, popular 

 poetry, and unpublished documents were referred to in support of this 



