A pollen study of a peat-bog sited in the  and the deforestation on 780±80 years . The results pinewood of Lillo (Leó n, Spain) is presented. The diagram have allowed to explain the autochthonous character of shows an initial phase where a well-developed pinewood Lillo pinewood, which remains as one of the few relics of was dominant with deciduous species, followed by a selective the southern slopes of the Cantabrian Range. clearance process of Pinus. Finally, the pinewood recovers again towards a similar state to that described at the

Keywords: plant taxonomy plant variation Iberian Peninsula epidermal characteristics needles PinusTaxonomic differences in the needle epidermis characteristics of Pinus sylvestris L. and Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells. P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while P. uncinata showed small, lateral subsidiary cells and nondifferentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of P. uncinata was also larger in diameter (15.1 ±1.8 um P. sylvestris; 21.1 ±2.8 umP uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the articular thickenings -all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features.

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Pollen analysis from a 14.1 m core recoverecd from a vally mire at Espinosa de Cerrato (Palencia, Spain), suggests that Pinus woodland has dominated thils area of the Northern meseta throughout almost the entire Holocene in contrast to many other locations in lbetia where early-Holocene conifer woodland was progressively replaced by deciduous taxa. This unique pattern ofvegetationi developmenit is attributable to a combination of continental climate, edaphic condition of thesas. Mesetas. and perhaps fire. These data suggest that vegetation in this area has been remarkably stable over an extended timescale and that arguments aconcerning Pinus communities not being native in the region are unfounded. Anthropogenic impact can be detected at c. 4500 14C yr BP, affecting evergreen Quercus woodlands, and between c. 3000 and 2000 14C yr BP affecting Pinus woodlands. The pine forests were replaced by plant communities resembling the present-day landscape (shrubs and cereals) from c. 1500 14C yr BP.