Acanthaceae has received considerable
taxonomic attention at the familial, subfamilial, tribal and subtribal levels.
Several different infra-familial classifications have been proposed for the Acanthaceae,
but no taxonomic consensus has yet been reached. The main objective of the
present study is to throw light on the phenetic relationships and to explore
the contribution of morphological and molecular characters in systematics of
Acanthaceae. The morphological data viz. macromorphology, stomatography, lamina
architecture and ISSR profiles of 30 Egyptian acanthaceous taxa were investigated.
The phenetic analysis using NTSYS-PC version 2.02 software based on 55
potentially informative morphological and molecular characters indicated that
the used morphological and ISSR criteria is likely to be useful and valuable
taxonomic traits. The morphological characters and ISSR aspects of all the
studied species produced a phenogram that showed two series; one of them had
two subseries, the first one comprised only three taxa while the second divided
into two clusters, each contained two groups. The delimitation and the membership
of the studied taxa clearly merit additional study using more criteria. The
phenetic analysis of both morphological and molecular attributes clarified the
segregation of genus Avicennia as a distinct identity away from Acanthaceae. Acanthus
mollis & A. montanus are isolated in its own series that comparable to
tribe Acantheae of the current taxonomic systems. The studied species of Thunbergia
are gathered its own subseries that comparable to tribe Thunbergiae and Ruellia
in its own group that comparable to tribe Ruellieae.