Grass genus is a term used to describe the scientific classification of grasses. The five solutions for this crossword are AVENA (5 letters), Festuca (7 letters), Poa (3 letters), Muhly (5 letters), and Stipa (5 letters). AVENA is a genus of annual and perennial grasses, Festuca is a genus of perennial tufted grasses, Poa is a genus of cool-season grasses, Muhly is a genus of perennial grasses, and Stipa is a genus of perennial grasses.