| The progress of systematic and taxonomic researches is summarized in Magnoliaceae which mainly involved the taxonomic systems, wood anatomy, chromosome, pollen morphology, plant chemistry, leaf morphology and anatomy, pollination mechanisms, breeding system, molecular biology, phytogeography and cladistic analysis. The above researches show that :the genera of Magnoliaceae have great similarity both in internal and external morphological characters and have obvious overlapping morphological characters, which make the delimitation of genera of this family ambiguous and divergent and there is controversy whether to set up the monotypic genera and oligospecific genera. In this paper, 35 species of Manglietia, Magnolia, Parakmeria, Michelia and Tsoongiodendron of Magnoliaceae from China have been comparatively studied by using paraffin sectioning to study the structure of leaf blades, main veins and petioles. The adaxial and abaxial leaf epidermis were also investigated under scanning electron microscope (SEM) in 35 species of the 5 above genera of Manoliaceae. The leaf venation patterns in 16 species of Magnolia, parakmeria, Michelia and Tsoongiodendron of this family were observed and described. The above researches were made in order to provide fundamental data in anatomy and discuss the taxonomic relationships between genera and under genera using the characters of leaf anatomy, leaf epidermis under SEM and leaf venation patterns.The leaves of Magnoliaceae are composed of epidermis, mesophyll and vein.There is thick or thin cuticle and many kinds of wax ornamentation on leaf epidermis, and the adaxial epidermical cells are smooth while the abaxial ones are smooth or papillous. The adaxial leaves of some species have hypodermis or not while the abaxial leaves have no hypodermis. Some species of Magnoliaceae have epidermical hairs only distributing on adaxial leaves while a few species have epidermical hairs both on adaxial and abaxial leaves. The hairs of Magnoliaceae are uniseriate unicellular or multicellular and there is one type of structure similar to "groove" on one side of the hairs and the multicellular hairs have "wrist" the number of which is different among species. The stomata distribute only on abaxial leaves and the type of it belongs to paracytic type. Trichome-base can be observed on some species which is different in shape among species.The mesophyll differentiate into palisade tissue and spongy tissue and the cells of palisade tissue line compact while the those of spongy tissue line loose. The shape of transverse section of main vein of leaves is semicircular and that of the petioles is semicircular or nearlyIIIround.The structure of transverse section of the main vein of leaves and petioles from outside to inside are composed of epidermis, cortex and vascular cylinder which contain vascular bundles, pith and pith rays and the vascular bundles are collateral ones.In most species,the phloem fibers of the main vein and petioles appear to be continuous and form a "ring" while in other species the vascular bundle is seperated from each other by paranchyma. Sclereids distribute in all petioles and some main vein and tannin cells distribute in mesophyll, main vein and petioles of some species. Oil cells are very common in all species of Magnoliaceae. The leaf venation of this family belongs to reticulated veins and the number of secondary veins and the angles between the basal secondary veins and primary veins are different among species. The characters of leaf anatomy, leaf epidermis and venation are useful to discuss the systematic relationships and the results are as following:(1) The Manglietia have continuous hypodermis and uniseriate unicellular hairs which have "groove" on one side of the hairs, so the results indicate that Manglietia is one of the most primitive taxon in Magnoliaceae which is in accordance with its taxonomic status in this family as a genus.(2) It is still divergent whether to set up the genus Parakmeria. This genera have thick cuticle but no hypodermis an...
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