Phylogenetics of Asphodelaceae (Asparagales): An Analysis of Plastid rbcL and trnL-F DNA Sequences
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Phylogenetic relationships of Asphodelaceae were investigated by parsimony analysis of 57 monocotrbcL nucleotide sequences, including 17 genera that have at some time been assigned to the family. All genera of Asphodelaceae except for three (Hemiphylacus, Paradisea and Simethis) form a strongly supported monophyletic group with Hemerocallidaceae and Xanthorrhoeaceae as their immediate sister taxa. In a second analysis, we added 34 plastid trnL-F sequences (an intron and a spacer between two transfer RNA genes) for the Asphodelaceae clade and nearest outgroup families (Doryanthaceae, Hemerocallidaceae, Iridaceae, Ixioliriaceae, Tecophilaeaceae and Xanthorrhoeaceae) in an attempt to improve resolution and levels of internal support. The results from the separate analyses produced highly similar although not identical results. No strongly supported incongruent groups occurred, and we combined both sequence regions in one analysis, which demonstrated improved results. Strong support exists for a monophyletic subfamily Alooideae, but this leaves a paraphyletic subfamily Asphodeloideae because Bulbine/Jodrellia alone are strongly supported as the sister group of Alooideae. Characters that have been used to separate Alooideae as a distinct group (either as here a subfamily or as a separate family by other authors), such as secondary growth and bimodal karyotypes, are found in at least some members of Asphodeloideae, particularly in Bulbine and Jodrellia for the karyotypes, making Alooideae less easily recognized.