STRUCTURE AND MICROMORPHOLOGY OF THE LEAF IN SOME TAXUS SPECIES.

In this paper leaf structure of 4 Taxus species and varieties (Taxus baccata, T. baccata var. fastigiata, T. brevifolia, Taxus cuspidata) was investigated. Histological and micromorphological studies were carried out by light and scanning electron microscopy. From the histo-anatomical point of view, the leaf shows a general structural pattern with palisade and spongy parenchyma. This is common to all investigated taxa with quantitative variations. The stomata are located only in the lower epidermis (hypostomatic leaves), being disposed on 2 bands, with different widths, on one side and the other of the midrib. The papillae of the cells from the lower epidermis are also visible next to the median rib, with the exception of the species T. brevifolia. The palisade parenchyma is bilayered, with short cells. The structural characters of the leaves have taxonomical significance. The importance of the structural features of the leaf in the adaptation of the species to the living environment were emphasized. [ABSTRACT FROM AUTHOR]