Morphological Diversity and Distribution of Etlingera littoralis (König) Giseke (Zingiberaceae) in Southern Thailand

Etlingera littoralis is a common ground species in Zingiberaceae. It is widely distributed in Peninsular Thailand both in the Gulf of Thailand and the Andaman Sea coasts. The morphological characters of E. littoralis and two related species, E. megalocheilos and Etlingera sp. are similar. Although E. megalocheilos were not found in this study, its morphological characters from previous studies indicated that E. littoralis and E. megalocheilos are different species. Interestingly, an unknown Etlingera sp. was found instead. The morphological character of Etlingera sp. is superficially similar to E. littoralis . The morphological characters of both E. littoralis and Etlingera sp. were studied using R statistic. The results showed that E. littoralis and Etlingera sp. can be clearly separated by reproductive parts (inflorescence color pattern, labellum length, labellum and stamen length ratio, and angle of anther). The morphological characters indicate that E. littoralis and Etlingera sp. can be classified as 2 different species.