Taxonomic Study of the Families Iridaceae, Colchicaceae, Melanthiaceae of Nepal and their Distribution Pattern

Abstract

Present study based on Angiosperm Phylogeny Group (APG III) system of classification of families Iridaceae, Colchicaceae and Melanthiaceae as a part of work of Flora of Nepal Vol. 10(Part I) consists of 8 genera and 19 species from Nepal. The present work is based on the morphometric evaluation of herbarium specimens deposited at different herbaria as BM, E, KATH, TUCH and TI. Predictive distribution modeling of the three families as Iridaceae, Colchicaceae and Melanthiaceae were done based on the presence only data from herbarium records and bioclimatic variables from WORLDCLIM using software DIVA-GIS 7.5 version. The species of families Colchicaceae, Iridaceae and Melanthiaceae possesses wide variation in the vegetative and reproductive characters. The species of family Iridaceae are delineated mostly on the basis of its floral characters i.e. falls having beard or ridges or simple. The species of family Colchicaceae are delineated on the basis of the chemical colchicines, while the species of family Melanthiaceae are delineated on the basis of their leaf, extrorse anthers and ovaries often with three distinct stigmas. The dendrogram based on cluster analysis of three families showed two distinct clusters. Cluster 1 consists of two families Colchicaceae and Melanthiaceae. These two families are closely related with each other and derived from the single family Liliaceae previously. Cluster 2 shows the species of family Iridaceae which are distinct from the rest of two families on the basis of its sword shaped leaves, three extrorse anthers and inferior ovary. Predictive current potential distribution of species of three families indicated that species of Colchicaceae are distributed in the Central and Eastern region of Nepal. The species of family Iridaceae are distributed in the North-Western region of Nepal and the species of family Melanthiaceae are distributed in the Mid-Western and Eastern region of Nepal.