Cytotaxonomical studies on Drimia nagarjunae and a review on the taxonomy of Indian species of Drimia

Abstract

The genus Drimia (Asparagaceae) is a group of tunicated bulbous plants. Eight species are found in India. However, their circumscription has always been controversial. The species, namely Drimia coromandeliana, D. govindappae and D. nagarjunae have been reduced to a cosmopolitan species D. indica. The species Drimia nagarjunae earlier described from Nellore District, Andhra Pradesh was never collected after the type collection. The present study reports the karyomorphological details of Drimia nagarjunae for the first time, since this species could now be collected from Chinnar wildlife sanctuary, Idukki district, Kerala. Amongst the Indian species of Drimia, D. nagarjunae (2n = 20) is the most robust species, with the mean chromosome length measuring 6.09 ± 2.40 μm, total haploid genome length 60.87 ± 2.40 μm. The longest chromosome pair measures 10.48 ± 1.28 μm while the shortest is 3.83 ± 0.39 μm long, and the pair number 6 had a satellite exhibiting the karyotype formula: 7st + 3t. Taxonomic notes on doubtful taxa (Drimia coromandeliana, D. govindappae and D. nagarjunae) have also been provided to elucidate the current status of the genus Drimia in India.