Taxonomic study on Lindernia All. (Linderniaceae) from some parts of South Eastern Nigeria

Abstract

The morpho-anatomical characteristics of Lindernia diffusa var. diffusa-in E. & P., L. oliveriana (Benth.) Wettst. and L. crustacea (L.) F. Muell.) were investigated with a view of providing additional line of evidence in the delimitation of the species in Nigeria. The specimens were subjected to microtomy. The anatomy, fruit morphology, leaf shape, number of fruits per node and, flower colour differed among the species. The species have two trichome types (glandular and non-glandular) with varying number of gland head and basal cells. The glandular trichomes have 4-7 gland heads and 4-8 basal cells while the non-glandular type-1 and 2 trichomes with 5-10 basal cells. Type-1 non-glandular trichome occurred in L. crustacean and L. diffusa var. diffusa while type-2 occurred in L. oliveriana. The palisade and spongy mesophylls are 1-layer and 3-5 layers respectively in L. diffusa var. diffusa, 1-2 layers and 4-6 layers in L. oliveriana and 2-3 layers and3 layers in L. crustacea. The palisade and spongy mesophylls are poorly differentiated. Two to five vascular bundles at the basal and distal ends of the petioles were observed in the Lindernia species with the main vascular bundle forming circular-united or fussed vascular bundles in L. diffusa var. diffusa and L. crustacea and arced or horizontally elongated vascular bundle separated by parenchymatous rays in L. oliveriana. In L. diffusa var. diffusa, the pith covered 55.99% of the stem, 24.27% in L. crustacea and 72.74% in L. oliveriana. These characters could be used to delimit the species studied.