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Tlemcen region is characterized by a Mediterranean climate, with a remarkable vegetal cover. The latter is influenced by the anthropozoological action. For that, we realized a phytoecological study based on the minimum area classical method [1] which allows us to have a good overview on plant biodiversity and better analyze and interpret the vegetation at different levels (systematic composition; biological, morphological and biogeographical characterizations; stratification; and plant species inventory which we hope comprehensive). The results show that our ecosystems are disrupted because therophytisation, before last vegetation dynamics element [2], settles giving up a few feet of cork and holm oaks species of ancient forest

This work was conducted to assess the anatomical features of Pistacia atlantica Desf. under Mediterranean semi-arid climate conditions. In this study, phytoecological approach was used at different observation scales including the large ecological scale. 11 samples of P. atlantica species were randomly selected in order to study the anatomy of leaves and branches. The results show that leaves have palisade parenchyma occupying almost the entire mesophyll, measuring 100 to 170 µm. While in branches, the only pith occupies 38% followed by the xylem (24%), relative to the rest of the tissue (epidermis, periderm, collenchyma, pericyclic fiber, secretory duct and phloem). The current results suggest that P. atlantica species has xeromorphic anatomical characters, giving it great ecological plasticity in an arid environment. Moreover, this study shows that the human activities are causing local extinction of this rare species in Algeria.

Dans ce travail les auteurs décrivent deux nouvelles stations d’Asplenium ruta-muraria L. Cette ptéridophyte, assez rare en Algérie et en Afrique du Nord, est découverte pour la première fois dans la région de Tlemcen. En effet, la rue des murailles n’a jamais été signalée dans cette région ni dans les anciennes flores algérienne (Battandier et Trabut, 1902 ; Maire, 1952 ; Quézel et Santa, 1962) ni dans les récent travaux sur les ptéridophytes en algérienne (Meddour, 2007, Medjahdi et al. 2013,...). Mots clés: Asplenium, chorologie, Région de Tlemcen, Algérie.Key words: Asplenium, distribution, rare species, Tlemcen, Algeria.

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