Mr. Ch. C. Babington on the Robertsonian Saxifrages. 465 



LV. — On the difference between the Robertsonian Saxifrages of 

 Ireland and those of the Pyrenees. By Charles C. Babington, 

 M.A., F.L.S., F.G.S. &c.* 



[With a Plate.] 



Having recently had occasion to re-examine the Irish Saxifrages 

 referable to HawortVs genns Robertsonia, I have been greatly 

 struck by the uniform difference which exists between each of 

 them and the corresponding plant of the Pyrenees. In a paper 

 contained in the 'Annals of Natm'al History^ (vol. viii. p. 321), 

 I have already shown that the typical Sax, umbrosa (the Pyrenean 

 plant) differs considerably from that foimd in Ireland, but was 

 not then aware that precisely the same differences exist between 

 the Sax. hirsuta and Sax. Geuin of those two countries. 



The differences to which I refer are found in the form of the 

 margin of the leaves, which may be correctly denominated " cre- 

 nate " in the Pyrenean plants, but to which the terms " acutely 

 crenate,^'' " serrate," or " dentate,^' must be applied when the Irish 

 specimens are described. The outlines of leaves which accompany 

 this paper will show what is intended far better than can be done 

 by any description. They have been carefully di'awn from the 

 leaves of specimens in my own herbarium, and belong to the 

 three above-mentioned species ; PL IV. fig. 1 — 7 representing the 

 leaves of Sax. umbrosa, fig. 8 — 10 those of Sax. Geum, and fig. 

 11 — 13 those of Sax. hirsuta. Of these, fig. 1, 8, and 11 are from 

 Pyrenean specimens, and all the others, except fig. 2 and 3, 

 from those found in Ireland. 



Saxifraga umbrosa. 



Plate IV. fig. 1. (from a specimen marked " S.umh'osa, Linn. 

 In M. Bulour propc thermas Eausbonnes, Pyr. occid. 1831." 

 Endress.) is the typical form of this species, in which the margin 

 is truly crenate, and does not appear to be a native of Ireland ; 

 but fig. 3, which is vmdoubtedly the same variety, is taken from 

 a plant possessing strong claims to be considered indigenous in 

 the West Riding of Yorkshire, where I have seen it in profusion 

 in Hezleden Gill, a wild and retired glen near the mountain 

 named Pen y Gent ; and the Rev. John Howson has found it in 

 Lynn Gill, which is situated on the opposite side of the Penine 

 chain of hills, and at a distance of about 4^ miles from Hezleden 

 Gill (Phytologist, p. 845). Another Pyrenean specimen, from 

 " Cascades du Lys, montagne d^Esquierry," being No. 27 of 



* Read before the Botanical Society of Edinburgh, 9th May, 1844. 



