Codonacanthus sanjappae sp. nov. (Acanthaceae) from Andaman and Nicobar Islands, India

Codonacanthus sanjappae Karthig., Sumathi, Jayanthi & D. Naras., a new species of the family Acanthaceae collected from the evergreen forests of Andaman Islands is described and illustrated. This is the first record of the genus Codonacanthus Nees on the Andaman and Nicobar islands. The new species is closely related to C. pauciflorus Nees but differs in glabrous branchlets, shorter inflorescence, glandular pubescent style and capsules. A detailed description and an illustration is provided. The genus Codonacanthus Nees, is comprised of two species, C. pauciflorus Nees and C. spicatus Hand.-Mazz., distributed in northeast India, southern China and Japan (Huang 1998, Mabberley 2005). During a floristic survey of Mahatma Gandhi Marine National Park, south Andaman, which includes 15 smaller and larger islands, plant collections were made in Rutland Island. A population of an unknown species was found growing in the ground vegetation of inland forests at lower altitudes. Critical examination of the specimens revealed that the plant belongs to the genus Codonacanthus, so far not reported from the Andaman and Nicobar Islands. Further investigation of the specimens and scrutiny of literature revealed that they show close affinity to C. pauciflorus but are significantly different in several vegetative and reproductive characters (Table 1). Consequently, the population found in Rutland Island is described as a new species here.