Bryophytes of the Wurm Lateglacial in the northern sector of the French Western Pyrenees

Bryophytes of the Wurm Lateglacial in the northern sector of the French Wes tern Pyrenees. Study of well-preserved macroscopic moss remains (stems, bra nches and leaves) present in a level of the Wurm lateglacial (13 860 +/- 12 0 yr BP), from a section in a Sphagnum bog at the Estarres (Ossau valley, A tlantic Pyrenees, France). Pollen analysis of the level shows that an hygro philous and hydrophilous vegetation with Poaceae, Apiaceae, Ranunculus, Tha lictrum, Sparganium, Potamogeton, Betula and Salix occurred in the lake dep ression of the Estarres. Bryum neodamense, Calliergon giganteum, Scorpidium scorpioides, Calliergonella cuspidata, Drepanocladus aduncus and Philonoti s sp. probably lived in fens at the lakeside (or even immerged in the lake in the case of the first three species). The occurrence of Eurhynchium spec ioslrm indicates the existence of very moist and shaded habitats, whereas P alustriella commutafa and Tortella tortuosa grew either on rocks or on bare calcareous soils that were respectively damp or dry. According to the Fren ch phytoecological data bank "Sophy", Bryum neodamense and Scorpidium scorp ioides are ecologically very similar to Calliergon giganteum. The three spe cies are presently no longer found at the site of the Estarres and are so f ar unknown from the Ossau valley and the Basque country, where the climatic conditions should however be suitable for them. Furthermore, these mosses are very ran in the Pyrenees. Finally, Sphagna, which are nowadays abundant at the Estarres, are absent from the studied level. (C) 1999 Adac/Editions scientifiques et medicales Elsevier SAS.