The need for rapid, reliable and accurate species identification is one if the goal of taxonomy. This is often achieved by the use of morphological characters. Regrettably, it is often fraught with unreliability. The application of numerical taxonomy has contributed to solving this challenge. Field identification of the five Vernonia species in Nigeria is very challenging. This study applied quantitative measurements of the leaf length, leaf width, petiole length, inter nodal length, twig length, length of mid rib, length of lateral nerves, and width of intra marginal nerves on thirty replicates per each of the five species to confirm significant differences. The species were grown in controlled environment and use of line thread and hand lens was used. The result showed that significant difference among all the species using leaf length existed with a minimum of 102.4 leaves from an individual plant was measured. In the same vein, the study showed that Leaf width was able to separate V. cinerea, length of twig was able to differentiate V. thompsoniana, length of mid rib was able to separate V. amygdalina while petiole length was able to differentiate V. conferta from others. With the exception of leaf length, no other character was able to discriminate V. colorata from others.