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This article assessed midrib anatomical description of Isolona Dunal. And Monodora Engl. (Annonaceae) from West-Central Africa. Twelve species of tribe Monodoreae were investigated on the basis of micromorphology of midrib characters with the aid of light microscopy. The study provided important taxonomic characters which aid delineation of inter and infrageneric species within the duo genera. The generic features include centrally positioned, open collateral vascular bundle and furrow shaped midribs which are diagnostic to the genera.U shaped vascular bundles are present in most of the species with inviginating or expanded endings while marginal traces vary from 2 to 4. The presence of keel protrusion at abaxial surface established a closer affinity among M. angolensis, M. crispata, and M undulata with additional features species were delimited. Other variable useful features of midrib encountered are trichomes, parenchyma, collenchyma and sclerenchyma, and adaxial and abaxial shape. The midrib characters have been used to prepare an indented dichotomous key to delimit the species in the genera studied. [ABSTRACT FROM AUTHOR]

This study shows that the populations of Acalypha fimbriata Schum. & Thonn. occurring in Nigeria are divisible into two recognizable varieties, viz., A. fimbriata Schum. & Thonn. var. fimbriata and A. fimbriata var. robusta Kadiri var. nov. Generally, the populations have a suite of similar characters in their vegetative and reproductive organs and the ultra-structures of the leaf cuticle using scanning electron microscope showed uniformity of characters like sunken stomata, wide-narrow stomatal opening and conspicuous periclinal wall. However, the two varieties are discriminated based on 1 vs. 2 fruits per bract, slim vs. robust stature, scanty vs. clumsy inflorescence on the axillary spike, leaf apex character as well as smooth and rough unicellular trichomes. The observation is supported by a T-test at 95% similarity confidence while the 14 populations consisting of 280 individuals used for the analysis are separated into two by the scatter diagram. Neighbour joining analysis using Euclidean measure and UPGMA dendrogram reveal the level of relationships. Therefore, one of the varieties is based on the description of the earlier described type specimen and the other variety being different is considered as a new taxon Acalypha fimbriata var. robusta Kadiri. [ABSTRACT FROM AUTHOR]