Seedling phenology of Clerodendrum indicum exhibiting the unusual epigeal cryptocotylar type of germination

Abstract

Clerodendrum indicum (L.) O. Kuntze (Lamiaceae) is characterized by some unique features in its seedling phenology and germination. The epigeal cryptocotylar type of seedling of the species is uncommon among dicotyledons. Significant morphological characters of the seedling of the species are thickened hypocotyl, a pair of cryptocotylar epigeal cotyledons and five pairs of eophylls in opposite decussate phyllotaxy. Each eophyll is ovate in shape with dentate margins and sub-acute apex. The eophylls are readily distinguishable from the foliage leaves of adult individuals by their architecture and phyllotaxy. The features are helpful in identifying an individual of the species at its juvenile stage, before flowering and fruiting. Clerodendrum indicum is the only known species of the order Lamiales that is characterized by the epigeal cryptocotylar type of seedling.