Phylogenetic relationships of Rhodolirium montanum Phil. and related species based on nucleotide sequences from ITS region and karyotype analysis

Abstract

The taxonomy of Chilean Amaryllidaceae is confusing. Taxonomic problems still persist at the level of genera and species. Currently there is controversy about the correct classification of species so far assigned to Rhodophiala C.Presl. Through the study of morphological characters, recently has been suggested the rehabilitation of the genus Rhodolirium Phil., where the species Rhodolirium montanum Phil. is considered as type species. This species was named Rhodophiala rhodolirion (Baker) Traub in traditional classifications. Since morphological data have provided limited and ambiguous information in the classification of Amaryllidaceae in Chile, this paper assesses the relevance of formalize the rehabilitation of genus Rhodolirium and particularly the resurrection of the species R. montanum, through an analysis of chromosomal morphology and nucleotide sequences of the ITS region of six native species of Amaryllidaceae. The molecular data indicate that the species Rhodophiala bagnoldii, R. montana, R. splendens, R. phycelloides and R. ananuca form a monophyletic group more closely related to Hippeastrum than Rhodolirium. This genus is presented as closely related to Phycella in the phylogenetic analysis using ITS sequences. This separation of Rhodolirium with respect Rhodophiala is supported by differences in chromosome number and morphology, presenting the first, chromosome number of 2n = 16 and intrachromosomal asymmetry index (Isc) of 0.46, while the latter has 2n = 18 and Isc of 0.59 to 0.62. Thus, chromosomal and molecular results together differences in exomorphology already mentioned by other authors support the rehabilitation of the genus Rhodolirium Phil. and the resurrection of the species Rhodolirium montanum Phil.