1904. Notes* 7,3 



But in additicm, there are in Comber, besides the'distillery, large flour 

 mills, which, though now, like most similar mills throughout Ireland, 

 idle, yet formerly did a large business and used a considerable quantity 

 of Egyptian wheat in the course of the trade. And my correspondent 

 has very kindly taken the trouble to ascertain that before this 

 Mediterranean wheat was ground^ it had all to be washed, so that 

 various seeds from this source must have found their way into the 

 Comber River. 



And when a map of Co. Down is examined, it is easy to see that at 

 every ebb-tide whatever floating matter, such as seeds or the like, is 

 carried by the Comber River into the head of Strangford Lough must 

 thence go south-east, which is precisely in the direction of the Ards 

 shore, and when it is borne in mind that the prevailing winds in Ireland 

 are from the west, it does not take a very elastic imagination to suppose 

 seeds from Comber distillery and flour mills finding a resting place 

 where were gathered the plants of Glyccria festticaformis on the Ards 

 shore. 



While the fact that these plants were found by Mr. Praeger nearer the 

 sea-water margin than the Aster Tripolium and Glyceria niaritima of the 

 indigenous flora, suggests their having only lately come there, and that 

 they have not yet had time to mingle more a-field with the true 

 natives. 



H. w. Lett. 



Loughbrickland, Co. Down. 



I have read Canon Lett's statement with much interest. In the fol- 

 lowing remarks I treat his hypothesis at some length, because it seems 

 to me that we field botanists sometimes fail to pay due regard to the 

 nature and value of evidence of cases of this kind, and proceed on lines 

 which cannot be classed as either logical or scientific. First, let me say 

 that I was not unmindful of the existence of distilleries and former 

 flour-mills at Comber. On many occasions during the last twenty years 

 I have f-tudied the alien plants which languish on the rubbish heaps 

 there. 



Canon Lett's theory is that seeds of Glyceria festuca:formis came to Com- 

 ber with foreign grain, were thrown into the Comber River, carried by 

 wind and tide down and across Strangford Lough, and obtained a foot- 

 hold along the several miles of coast on which at present the plant is 

 known to grow. Now, to bring the hypothesis within the range of pro- 

 bability, several factors must contribute. First, some evidence is required 

 of the probability, or even possibility, of the seed of the grass reaching 

 the distillery or flour-mill. What is the case as regards this point? 

 The foreign grain which is quoted as having been used at Comber, is 

 barley from Algeria, and wheat from Egypt. Now, G. festucceformis does 

 not grow in Algeria, nor in Egypt, nor indeed anywhere on the southern 

 shores of the Mediterranean ; and with the failure of this key-stone of 

 the arch, where is our hypothesis? 



