Phylogeny, biogeography, and character evolution in the genus Scilla s.l. and its close relatives Chionodoxa, Gemicia, Puschkinia, and Prospero (Asparagaceae)

Abstract

Scilla s.l. is taxonomically one of the most problematic genera of the Asparagaceae. Within the last few decades, several genera were segregated from this genus; however, there is still no consensus on the taxonomic status of Scilla segregates. Although some previous studies indicated a polyphyletic origin for the genus Scilla, there has been no comprehensive phylogenetic study focusing on the entire complex including Chionodoxa, Prospero, Puschkinia, and the recently described Gemicia. To achieve this, we evaluated three plastid regions, namely rbcL, trnL-F, and matK, for 79 accessions. The monophyly of Puschkinia and Prospero was supported by our phylogenetic analyses; however, Chionodoxa and Gemicia were placed into a clade with representatives of the S. bifolia species group. While our divergence time estimation analysis indicated a Miocene origin for all studied genera of polyphyletic Scilla s.l., the results of our ancestral area and ancestral state analyses showed that Scilla, Prospero, Chionodoxa, and Puschkinia, together with Brimeura Salisb., Bellevalia, Hyacinthella, and Alrawia, probably had a most recent common ancestor without a perianth tube and a corona, and with a non-papillate testa surface, which evolved about 36 Ma in the Mediterranean region.