MICROMORPHOLOGY, KARYOLOGY AND PHYTOCHEMICAL STUDIES ON THE CARALLUMA ADSCENDENS (ASCLEPIADACEAE) COMPLEX IN TAMIL NADU, INDIA

Abstract

Caralluma adscendens (Roxb.) R. Br. (Apocynaceae) is a wild growing variable succulent herb distributed frequently in drier regions of Peninsular India especially more diversified in Tamilnadu. Seven varieties under the taxa recognized and they have given detail morphological and distributional notes for these varieties. Local Floras are not treating these varieties properly and still exhibits controversy in the identification on these taxa. The present study emphasizes on the floral micro-morphology, chromosome numbers and amount of flavonoid compounds in each variety, resulted that clear differences showed between each varieties. Specifically rounded angle varieties namely var. adscendens, attenuate, bicolor and fimbriata are possessed uniform chromosome number (2n = 22), whereas acute angled varieties such as var. carinata and var. gracilis are having tetraploid (autoploid 2n = 44). Var. geniculata is reported only 2n = 22 chromosomes but it has acute angled with phytogeographically segregated in nature when compared to all other varieties. The present study provided separate manual keys for Caralluma adcendens and their varieties based on the stem morphology, corolla epidermal micromorphology, karyology and chemical compounds present in them. This study would be supported that the elevation of var. geniculata into species level as Caralluma geniculata mentioned by Meve and Leide (2002).