A NEW SUBSPECIES OF PEDICULARIS SYLVATICA L. 



241 



that the plant is very common in most of the West of Ireland and distinctly rare in the 

 East and Centre. 



The few outlying stations, somewhat cut off from the main areas of distribution, are 

 as follows : 



Co. WATERFORD : Exposed moorland at 550 ft. between Ardmore and Dungarvan, 02/1149, D. A. 



Webb and W. A. Watts, Sept. 1954. 

 Co. WICKLOW : Calary Bog, R. L. Praeger, 1895 (Herb. Nat. Mus. Ireland). 



Kilbride Camp, R. L. Praeger, 1904 (Herb. Nat. Mus. Ireland). 

 Co. SLIGO : Bog near Cliffony, E. J. Archer, July 1950 (Herb. T.C.D.). 



Co. TYRONE : Near Omagh, M. C. Knowles, 1896 (Herb. Nat. Mus. Ireland). 



Co. FERMANAGH : Tappaghan Mt., N. of Lack, 05/43, R. D. Meikle, May 1955. 



It will be noticed that in three of these stations the plant is of an intermediate type - i.e. 

 only slightly hairy. 



Outside Ireland this subspecies is known with certainty only from a single locality 

 in the Hebrides - the islet of Scalpay which lies off the east coast of Harris. Two separate 

 gatherings from this station, both in the British Museum, are exactly similar to plants 

 from the West of Ireland ; one was collected by J. W. Campbell, the other by A. J. Wilmott, 

 M. S. Campbell and E. B. Bangerter. There are, in the same herbarium, fourteen other 

 gatherings from the Outer Hebrides (Scalpay, Barra, Benbecula, Harris, Lewis), and 

 they are all typical subsp. sylvatica. There is one other Scottish plant apparently of 

 subsp. hibernica in the British Museum herbarium, collected by Pugsley in Glen Callater, 

 Aberdeenshire, on 30 July, 1923. But as it is labelled " fl. albis " and the specimen has 

 indubitably pink flowers, it would appear that a transposition of labels may have taken 

 place, and it cannot be accepted as it stands. But the occurrence of the subspecies in a 

 few localities in the Highlands is by no means improbable. 



On a vice-comital basis its distribution as at present known is : 110; H 1, 2, 3, 6, 

 8, 9, 16, 20, 27, 28, 33, 35, 36. 



In almost all localities in the West of Ireland in which hairy plants are found it is 

 possible to find normal glabrous ones as well. The ratio of hairy to glabrous is roughly 

 proportional to the longitude : in the extreme west it rises to something like 20 to 1, and 

 as one approaches the eastern boundary of the continuous distribution of subsp. hibernica 

 it falls to unity or less. Plants of an intermediate (only slightly hairy) character are not 

 very common, and they seem to occur chiefly near the eastern limit of subsp, hibernica. 



This hairy form seems, therefore, undoubtedly to deserve subspecific rank; it is 

 morphologically discriminable although intermediates exist, and it has a well-defined 

 geographical area, with a fairly narrow zone of overlap. I should be grateful for any 

 reports of its occurrence in regions other than those which are here set out in the map. 



Three possible hypotheses as to its history can be entertained. (1) It could be 

 endemic to the British Isles, dating from interglacial or pre-glacial times, and have 

 survived one or more glaciations in refuges on the western seaboard, more successfully 

 in Ireland than in Scotland. (2) It could be of post-glacial origin in Ireland, and have 

 spread to Scotland by a chance of long-range dispersal. (3) It could have survived the 

 last glaciation in south-west England or western France, spread to Ireland and Scotland 

 early in the post-glacial, and subsequently undergone fragmentation, including extinction 

 in all its original territory. None of the hypotheses seems thoroughly plausible; on the 

 whole I prefer the first. It must be remembered, however, that typical P. sylvatica seems 

 less hardy than one might imagine : it is not found north of 64°N. in Scandinavia, nor 

 above 1,110 m. in the Alps. 



