THE DISTRIBUTION OF PADINA PAVONICA 41 



presence of areas sheltered from long Atlantic fetch into the English Channel from the west. 

 Three record groups are evident : 



(a) the Saint- Vaast-Tatihou-Barfleur area of the east-facing coast; 



(b) the Cap Levy-Cherbourg-Querqueville area of the northern Cotentin coast, sheltered 

 from fetch by Cap de la Hague ; and 



(c) the Blainville-Chausey-Granville area of the southern half of the long west-facing coast, 

 protected from fetch by being well within the Golfe de St Malo. 



These groups of records also reflect the main areas where cliffs and rocky foreshores abut 

 stretches of low water sands, giving shallow detrital pools. On sandy east Cotentin, rocks occur at 

 Hameau and Quineville; further north lies the classic area of la Hougue and Tatihou. From 

 Saint- Vaast-la Hougue to Barfleur the coast is low, with rocky platforms (reefs) covered by dense 

 algal growths. Saint- Vaast and Tatihou show slightly stronger wave-action than elsewhere in the 

 vicinity (Fischer-Piette, 1932) but there is no really wave-beaten rock surface. Granitic rocks occur 

 along the north coast from Pointe de Barfleur (Gatteville) to Cap Levy; outcrops are at first 

 isolated in a primarily sandy shore, but about Cosqueville become more continuous, below cliffs. 

 From Cap Levy to Cap de la Hague, the east<->west trend of the northern coast is roughly main- 

 tained, the cliffs descending westwards, towards sandy Urville. West again, other high cliffs 

 terminate just before the low granite promontory of Pointe de Jardheu. Western coast headlands 

 are mainly of more resistant rocks, and the long (more than 1 km) Pointe du Roc; the town of 

 Granville, at the entrance to Baie du Mont St-Michel, stands on the latter. Between these two 

 major headlands, wide belts of sand dunes occur, with intermittent wide rocky reefs bordering 

 them to seaward. 



Local presence of tolerable substrate conditions has been emphasised, since so important to 

 Padina. Other environmental aspects are unlikely to restrict Padina distribution here; Cabioch 

 (1969) maps many such aspects for areas west of Cherbourg. Local abundance of areas in which 

 Padina could be expected to occur indicates that past collecting patterns must have strongly 

 influenced the mosaic availability of data. The long history of collection and observation from 

 Saint Vaast-Tatihou reaches back at least to 1 831 (see Hariot 1912 : 2-3 for an historical summary); 

 collecting in that area was stimulated by the foundation (1881) of the Laboratoire de Tatihou. 

 Cherbourg area is well known, mainly through visits by Thuret (1846, 1850, 1863, 1866, 1874, etc.), 

 accompanied by Bornet from 1852 onwards. Le Jolis, born and resident in Cherbourg, studied 

 with Bornet and Thuret; both gave considerable help with his Liste des Algues marines de 

 Cherbourg (1863, 1864, 1880). Bornet, Thuret, and Le Jolis also frequently visited the Saint- Vaast 

 area, although Le Jolis is said to have preferred Cherbourg for algae. Padina data for Granville 

 area were initially recorded by Pelvet, important comparative information being later provided by 

 Davy de Virville. Harvesting of algae seems then to have been causing deleterious effects on 

 Padina and the whole littoral ecosystem. Current comparative data are now required. 



Channel Islands 



Alderney: 



Fort Houmet: Marquand (1901); van Heurck (1908), pool near there. 



General: C. B. W. Brook, seven plants, one 29.viii, two others 19.ix, rest undated, all , 

 acquired 8.vii.l920 (BM); Lyle (1920); Chemin (19346), great development of rocky shore facies 

 algae at all levels, muddy facies flora very rare to non-existent, Padina reported by Marquand, 

 Taonia not at all. 



Guernsey : 



UAncresse: Lyle (1920). 



PortSoif: 5.ix.l960, D. Hepper, four plants, all 0, P88/1/1 1 (PLTH); Dixon(1961), 5.ix.l960. 



Grandes Rocques: Marquand (1895, 1901); van Heurck (1908); Dixon (1961), lower mid- 

 littoral and sublittoral, ix.1960, D. Hepper (Ballantyne). 



Cobo (Long Rock): Dixon (1961), lower midlittoral and sublittoral, ix.1960. 



Cobo: 10.viii.1883, E.George, in bay(BM);25.ix.l893,31.viii.!894,E.D. Marquand (NMW); 



