A Survey of Verbena xutha Lehm. (Gulf Vervain) Morphological and Cytological Characteristics

Gulf vervain (Verbena xutha) is a herbaceous perennial native to the southern United States. The species produces attractive spike inflorescences that provide a source of food for many pollinators. Besides botanical classifications, pollen morphology and cytological traits of this species have not been documented until now. Gulf vervain was found to have 2n = 42 chromosomes, with the first report of 2C nuclear DNA content of 2.95 pg. Convex-triangular pollen grains averaged 37.18 μm in diameter, with 84% stainability after cotton blue staining to estimate pollen viability. This information brings light to the genetic makeup of gulf vervain and may aid in future breeding programs.