COMPARATIVE MORPHOLOGY AND ANATOMY OF THE LEAF AND STEM OF PEPEROMIA DAHLSTEDTII C.DC., OTTONIA MARTIANA MIQ. AND PIPER DIOSPYRIFOLIUM KUNTH (PIPERACEAE)
Oliveira,J. H. G.
The genera and species of Piperaceae show a considerable structural diversity of leaves and especially stems. This paper presents a comparative morphological and anatomical study of the leaves and stems of three common Brazilian species of this family (Peperomia dahlstedtii C.DC., Ottonia martiana Miq. and Piper diospyrifolium Kunth), the vegetative organs of which have previously been little studied. The collected plant material was fixed in FAA, cut freehand and stained in safranin and astra blue. P. dahlstedtii is an epiphyte and has a herbaceous stem with whorled leaves phyllotaxis and a polystelic structure, a multiseriate adaxial leaf epidermis and calcium oxalate monocrystals in parenchyma and collenchyma petiole cells. O. martiana and P. diospyrifolium showed strong similarities, both being terrestrial plants, with alternate phyllotaxis, stele with medullary bundles and dorsiventral leaves with an epidermis and subepidermic layer. In O. martiana the stomatal complex is staurocytic and presented silica crystal sand in parenchyma petiole and midrib cells. In P. diospyrifolium the stomatal complex is tetracytic and there are calcium oxalate raphide crystals in the parenchyma of the petiole and midrib cells. On the other hand, the three species show some structural likenesses in that all have hypostomatic and dorsiventral leaves, oily cells in petiole and mesophyll, secretory trichomes and an endodermis with Casparian strips.