any of a large genus (Penstemon) of chiefly North American plants of the figwort family, having five stamens, the fifth of which is bearded and sterile, and bearing tubular, showy, white, pink, red, blue, or purple flowers
See penstemon in American Heritage Dictionary 4
(pĕn-stēˈmən, pĕnˈstə-mən)
noun
Any of numerous plants of the genus Penstemon, native to North America and eastern Asia, having opposite leaves, flowers with a usually two-lipped, variously colored corolla, and capsules containing many seeds. Also called beardtongue.