THE DISTRIBUTION OF PADINA PAVONICA 31 



past appearance at Aberdeen. At least, in Anglesey, there seems not to have been interpretational 

 error during data transcription. 



Lancashire 



Isle of Walney : 



Hudson (1762), '. . in littore Insulae Walney, sed rarius . . .' (as Fucus pavonicus). 



This record is secondarily published in: 



Martyn (1763); Robson (1777); Greville (1830); Batters (1902); Martindale, Holmes [& 



Batters] (1906, 1920). 



Hodgson ( 1 876, 1 877), reporting collections from Furness, gave a description of shores around 

 Walney: '. . . The high reaches of Morecambe Bay, as at Aldingham, Baycliff, and Ulverston, were 

 always greatly influenced in their fertility by the position of the channel and the shifting of the 

 sands. If the deep water ran up for a time on the east of Chapel Island, or at least pretty well 

 out from these shores ; then the old boulder clay (scars as they are called) would appear, washed 

 from their thick covering of fine sand. . . . These long out-runners, or points, after re-exposure to 

 light, air, and fine summer weather, are speedily clad with a rich verdure. Green and olive 

 coloured plants of the most delicate structures fringe the small tide-pools, barely getting time to 

 mature their loveliness ere huge bosses of tangle come and contest the ground. . . .'. Consolidated 

 boulder clay surfaces could well have supported ephemeral growth of Padina. They are very like 

 the substrata at, for example, Bembridge (Isle of Wight), where plants grow well. Hodgson (1876) 

 was already not prepared to say '. . . whether there is much favourable ground for the study of 

 marine botany on the coast of Furness now . . . Clean, sweet waters, with but a moderate supply of 

 mud are essential conditions to the growth of these beautiful plants, and in this respect Roa Island 

 had some time ago greatly fallen off . . .'. More than a century earlier, when the single known 

 original record was established, conditions were probably rather better. Hudson had some as yet 

 unidentified but definite connection with the Isle of Walney; he knew the circumstances of the 

 Padina there reported sufficiently well to add confidently '. . . sed rarius'. We accept, in the absence 

 of contrary proof, that this could have been a chance fleeting occurrence in the same category 

 as the recent find by Cullinane in Fennels Bay, Co. Cork (q.v.\ Ketchen (1965 : 23) indicated that, 

 even recently, many brown seaweeds (not naming Padina) are on Walney Island attached to stones 

 in the littoral or thrown up in drift. The possibility of future ephemeral finds of Padina is therefore 

 not excluded. 



Ayrshire 



Ayr: 



in Coll. J. MacNab, not dated [mid 19th century] (DBN). 



Ayrshire coastlines are essentially sandy, but there are rocky outcrops at Prestwick; north of 

 the mouth of the River Ayr; and, especially, forming the south side of Ayr Bay from near Doonfoot 

 down to the north side of Culzean Bay (Heads of Ayr). Ephemeral stabilisation of detritus tolerable 

 to Padina could therefore occur. After substrata, primary factors of importance to Padina seem 

 to be the levels of insolation and temperature. Locally accurate treatment of the effects of these 

 parameters is not feasible; apart from sheer lack of data about shore environmental parameters, as 

 Russell (1973) has recently indicated, studies in benthic marine ecology are on the whole not 

 sufficiently sophisticated to identify precisely the environmental causes of biological events. 

 Generally, this Ayr record, one of the most northerly after those from Aberdeen (discounted) and 

 Argyllshire (drift and doubtful), is the only one from an area with mean August sea surface 

 temperature below 14 C. Wade's Connemara record (see Co. Galway) is the only other from an 

 area with mean August temperature below 15 C, and that record is also doubtful. Ayr lies in the 

 coastal area with average summer sunshine hours lower than elsewhere in the British Isles. By 

 contrast, major British populations of Padina occur in areas where (i) mean sea surface temperatures 

 are generally greater than 16 C (August) and average maximum summer air temperatures are 

 greater than 20 C; (ii) average summer sunshine hours are greater than elsewhere in the British 



