Supplementary Material for: Confirmation of Natural Hybridization between <b><i>Kengyilia</i></b> (StStYYPP) and <b><i>Campeiostachys</i></b> (StStYYHH) (Triticeae: Poaceae) Based on Morphological and Molecular Cytogenetic Analyses

Natural hybridization has been frequently observed in Triticeae; however, few studies have investigated the origin of natural intergeneric Triticeae hybrids. In the present study, we discovered three putative hybrid Triticeae plants in the Western Sichuan Plateau of China. Morphologically, the putative hybrids were intermediate between <i>Kengyilia melanthera</i> (2n = 6x = 42; StStYYPP) and <i>Campeiostachys dahurica</i> var. <i>tangutorum</i> (2n = 6x = 42; StStYYHH) with greater plant height and tiller number. Cytological analyses demonstrated that the hybrids were hexaploid with 42 chromosomes (2n = 6x = 42). At metaphase I, 12.10–12.58 bivalents and 13.81–14.18 univalents per cell were observed in the hybrid plants. Genomic in situ hybridization demonstrated that the hybrids had StStYYHP genomes. Phylogenetic analysis of <i>Acc1</i> sequences indicated that the hybrids were closely related to <i>K. melanthera</i> and <i>C. dahurica</i> var. <i>tangutorum.</i> Our morphological, cytological, and molecular analyses indicate that these hexaploid natural hybrid plants may be hybrids of <i>K. melanthera</i> and <i>C. dahurica</i> var. <i>tangutorum.</i>