Taxonomic Study of Some Euphorbia L. Species by Leaf Anatomical and Molecular Characteristics Using RBCL and Matk Genes

A current study assessed the leaf anatomical and molecular characteristics of eight species of the genus Euphorbia (Euphorbiaceae), i.e., E. craspedia Boiss, E. denticulate Lam., E. falcate L., E. hirta L., E. helioscopia L., E. peplus L., E. kansuensis L., and E. macroclada Boiss ,collected from several districts of the Middle and Northern Iraq. The anatomical result refers to a uniseriate epidermis (single layer), except for the species E. kansuensis and E. peplus, wherein the upper epidermis recorded a variable thickness among the species. The highest epidermis thickness (28 μm) was visible in the species E. falcata, while the mean decreased to 17 μm in the species E. helioscopia. Based on the anatomical attributes, further species groupings resulted in two. In the first group, the leaf’s crosssection was unifacial, with the palisade tissues on both sides of the blade. This group included E. hirta, E. peplus, E. macroclada?, and E. denticulata. Contrastingly, the second group has a bifacial leaf, with the mesophyll distinguished as palisade and spongy. The said group comprised the E. craspedia and E. helioscopia species. In the genus Euphorbia species, the study of the genetic relationship continued according to the sequencing method of rbcl and matk genes. The results revealed that most species samples showed light bands, characterized by their intensity ranging from 800 to 1000 bp. The highest recorded genetic affinity through the rbcl gene emerged in E. denticulata and E. kansuensis, whereas the lowest was in E. macroclada and E. hirta. Based on matk gene results, the highest genetic affinity observed resulted in the species E. kansuensis and E. denticulata with an average value of 0.0160, with the lowest recorded in the species E. helioscopia and E. peplus with a value of 0.1307.