The Plantaginaceae

The Plantaginaceae includes most (not all) of the remaining plants with bilaterally symmetrical corollas of 5 fused petals. They do not have deeply lobed ovaries that form nutlets and they do not have touch-sensitive stigmas.

Check your understanding:

Some common members of the Plantaginaceae are in the genus, Penstemon. Presumably, this name refers to the fifth stamen, which is a staminode. In some species, this staminode is glabrous, but in some, it is quite hairy and many species of this genus have common name "beardtongue".