Histological analysis of petiole structure in Euphorbiaceae species for taxonomic classification

The current study was carried out to describe the taxonomic microanatomical traits of petiole micromorphology of Euphorbiaceous species inhabited in desert rangeland. The petioles were sectioned using a Shandon Microtome and observed under a microscope to assess both qualitative features (shape, size, and arrangement of cells) and quantitative features (cell dimensions and tissue proportions). Eight Euphorbiaceous species were examined for petiole micromorphological characteristics including shape and size of the petiole, collenchyma cells, parenchyma cells, epidermal cells, and number and shape and arrangements of vascular bundles. The maximum petiole length was measured for Euphorbia helioscopia L. (330 µm). Maximum 9 numbers of vascular bundles were observed in Euphorbia serpens Kunth. Winged petiole was examined in three species of Chrozophora plicata (Vahl) A.Juss. ex Spreng., Chrozophora tinctoria (L.) A.Juss., and Croton bonplandianus Baill. In Euphorbia hirta L. and Euphorbia serpens Kunth. Trichomes were present non-glandular and unicellular. Euphorbiaceous species were also diagnosed using micro-petiole traits with the help of taxonomic key. The statistic tool via PAST3 software using dendrogram clustering and principal component analysis was used for the accurate species delimitation. The explored microanatomical features were used to distinguish the Euphorbiaceous species significant for further phylogenetic interpretation.