Cheloneae

Mourad, Magdy M., 2015, Diversity and evolutionary trends in the floral characters of some taxa of Scrophulariaceae sensu lato, Adansonia 37 (1), pp. 149-159 : 156

In tribe Cheloneae

Russelia equisetiformis occupies the lowest position vs Scrophularia xanthoglossa . The former species exhibits a considerable number of less advanced characters viz. five distinct sepals, sepal median bundles origin from the central stele, numerous sepal vascular bundles, five petals, dithecous anthers, five staminal traces from the central stele, dorsal carpellary bundles arose from the central stele, lateral carpellary bundles numerous, nectariferous disc vascularized and the compitum is wanting. Scrophularia xanthoglossa shows several advanced characters viz. sepal median, sepal marginal and petal bundles protruding from vascular complexes, bilipped corolla tube (2,3), monothecous anthers, one suppressed staminal bundle, two ventral carpellary bundles, non-vascularized nectariferous disc and presence of a compitum. Paulownia tomentosa acquired the second level of primitiveness after the Russelia among the studied taxa, owing to the subsequent characters viz. five sepals, sepal median, sepal marginal, petal, staminal and dorsal carpellary bundles arising from the central stele, five petals, dithecous anthers, lateral carpellary bundles from the dorsal carpellary mass, four ventral carpellary bundles and absence of compitum.