Feb. 1891.] BOTANICAL SOCIETY OF EDINBURGH. 59 



surroundings of the plant, and to ascertain, if possible, 

 whether such variations appear to be constant or are per- 

 petuated by seed. 



It is only by the laborious collection of such data over 

 a wide field, and comparison of them by many observers, 

 that a real solution of some of the more difficult evolutionary 

 problems may eventually be hoped for. 



But, hitherto, such variations have almost entirely been 

 examined by the naked eye or hand lens only, and the study 

 of them has been greatly left to the group of botanists often 

 contemptuously spoken of as " species-mongers." My aim 

 will be to show that detailed microscopic examination is 

 necessary if we are to appreciate fully their value in unfold- 

 ing to us the relation which one species bears to another. 



The Galway region of Ireland has proved exceptionally 

 rich in Ericas, for there have already been recorded E. 

 ciliaris, E. meditcrranca, E. cinerca, E. Tctralix, and E. 

 Mackayi, while there now falls to be added that form 

 mentioned by Dr Craig at last meeting as having been first 

 observed by Dr Stuart, and for specimens of which I am in- 

 debted to Mr Boyd and Mr Lindsay. I shall deal with 

 these in the order mentioned. 



E. ciliaris. — First recorded from Cornwall.* This species 

 was found at Pioundstone in 1846 by Mr J. F. Bergin, and 

 by Professor Balfour in 1852. Two sheets of it occur in the 

 herbarium of the Eoyal Botanic Garden, Edinburgh, one in 

 Professor Balfovir's writing, " near Eoundstone, August 1852." 

 Another with label, " Herb., Trin. Coll., Dublin," from the 

 same locality but bearing no date, nor have I identified the 

 writing as yet. I may here state that E. Watsoni, from 

 Cornwall, is a perfectly blended histological reproduction, of 

 its parents, E. ciliaris and E. Tctralix. 



E.mediterranca. — This species is found a few miles from the 

 locality above given for E. ciliaris; and, as stated by Professor 

 Babington in 1836, " it is in the greatest plenty, occupying 

 the valley for more than a mile, and growing in tufts of 

 from one to two feet in height." The members of the club 

 can confirm this description. 



E. cincrea. — As is usually the case on heaths, this 

 species is very abundant about Eoundstone. 



* Cybele Hibernica, 1866. 



