CYTOTAXONOMY OF THE SPECIES AND INTERSPECIFIC HYBRIDS OF THE GENUS AGROPYRON IN CANADA AND NEIGHBORING AREAS

Abstract

A cytotaxonomic treatment is given for 10 native species, 4 introduced species, and 8 natural interspecific hybrids of the genus Agropyron Gaertner that occur in Canada. Five of the native Agropyron species, one introduced species, and one natural interspecific hybrid are also found in Alaska. Eight of the native species, the four introduced species, and four natural interspecific hybrids are present in the mainland United States. Four additional native species and five additional introduced species that occur in the mainland United States are considered briefly.Nomenclatural proposals include: Agropyron dasystachyum (Hook.) Scribn. var. riparium (Scribn. & Smith) Bowden; Agropyron × pseudorepens Scribn. & Smith (pro sp.) nm. pseudorepens and nm. vulpinum (Rydb.) Bowden (A. dasystachyum × A. trachycaulum); and Agropyron × brevifolium Scribn. (pro sp.) (A. scribneri × A. violaceum).Voucher specimens are cited for chromosome number determinations of the native and introduced Agropyron species and some natural and artificial interspecific hybrids. Chromosome numbers are reported for the first time for A. violaceum (2n = 28), A. yukonense (2n = 28), the natural hybrids A. × pseudorepens nm. pseudorepens and nm. vulpinum (2n = 28), A. dasystachyum × A. spicatum (2n = 21), and A. violaceum × A. yukonense (2n = 28), and four artificial interspecific hybrids. Seven natural hybrids and four artificial hybrids are reported for the first time.