1 12 The Irish Naturalist. 



taury ; Caleb Threlkeld, too, the father of Irish botany, as he may be 

 called, in a note in his "vSynopsis Stirpiuni Hibernicarum " (Dublin 1727) 

 observes: — " that many plants which commonl}* bring forth purple or 

 blew flowers do vary into white or flesh-coloured, as Biigula, Digitalis, 

 Centaurium minus'''' {Bugiila and Centaurium minus being here old synonyms 

 for Ajuga reptans and Erythrma centaurium) ; while Haller, in the second 

 edition of his splendid work on the Swiss flora — "Historia Stirpium 

 Indigenarum Helvetice " — Berne, 1768 — records the occurrence of White 

 Centaury at two stations in northern Switzerland. 



As for the sports of Ajuga reptans and Prunella vulgaris noted by Mr. 

 Moffat in the January issue of the Irish Naturalist, they have been long 

 recognized by botanists. Haller quotes Jerome Tragus of Strasburg, who 

 wrote about the middle of the i6th century, as having recorded the red 

 variety oi Prunella, and Tabernsemontanus (A.D, 1590) the white, both of 

 these varieties having been observed in Switzerland by Haller himself, 

 the white, as he tells us, in hilly stations, the red in gravelly tracts. 



Every practical botanist must early have noted in flowers the superior 

 permanence of yellows to blues and purples, and will agree with the 

 opinion expressed by Haller in the preface to his Swiss flora, where, dis- 

 cussing the value of colour as a specific mark, he lays it down that while 

 yellows are rarely deceptive, blues and purples are frequently so. 

 Increase of elevation above sea-level, I have myself frequently observed 

 to be accompanied by a blanching of blue and purple flowers, as in the 

 Field Gentian {G. campestris) and the common Marsh Thistle (Cnicus p)ci- 

 lustris) which, purple, as a rule, in the lowlands, are often white in the 

 hills. Any attempt, however, to connect this blanching with one or more of 

 the many changes of conditions necessarily or accidentally attendant upon 

 change of elevation would soon lead the inquirer beyond the domain of 

 botany pure and simple into the fields of biology and organic chemistry. 



Perhaps some reader of The Irish Naturalist with the necessary attain- 

 ments in these provinces could throw light on this very interesting 

 subject. Field botanists by systematic observation of the obvious changes 

 of condition accompan3ang changes of colour, would, no doubt, help 

 towards the solution of the problem. — N. CoiyGAN, Dublin. 



The Tree Mallow (Lavatcra arborca) in Ireland. — As Mr. 

 Praeger mentioned {Irish Naturalist, vol. ii., page 53.) the Tree Mallow, 

 as growing on isolated and precipitous rocks on Rathlin Island, on the 

 north coast, it may interest readers to hear of the same plant in similar 

 situations off the south-west coast. Large bushes of it may be found 

 growing on the " Little Skelligs Rock," which is fully eight miles from 

 nearest point of mainland, and ten, at least, from nearest houses on 

 mainland. The Little Skelligs is ver}^ precipitous, rising in broken 

 pinnacles to about 600 feet ; it is and always has been uninhabited, except 

 by the myriads of sea-birds which frequent it in the breeding season ; so 

 far as I have noticed on various visits it is totally unfrequented by any 

 seed-eating birds. ^ 



Another plant I may mention which grows in great luxuriance is 

 known here as "Skellig Spinach," and used as such — I think it is known 

 as "Good King Henry" — and yet another very abundant growth there, is 

 a very large-leafed Sorrel. These with great tufts of Thrift, both pink 

 and 7uhite grow above the wash of the heavy Atlantic rollers that inces- 

 santly break round the foot of the cliffs. — Ai^Ex. De;IvAP, Valencia Island. 



ZOOLOGY. 



MOLLUSCS. 



Valvata cristata in Co. Cork.— It is stated in the December 

 number of The Irish A'atitralist (vol. i., p. 178) that the above shell seems 

 quite absent from the south-west of Ireland. I have, therefore, much 

 pleasure in recording it from this district, having collected specimens in 

 the slow streams near Cork park, about one and a-half miles from he 

 city.— R. A. Phii^lips, Ashburton, Cork. 



