Are Herbertia and Ammobium both perennial plants?
Herbertia (plant) Herbaceous and perennial plants, from tunicate, ovoid bulbs with brown, dry, brittle and papery tunics. The stems are simple or branched. The leaves are few, with the basal ones larger than the others; the blade is pleated, linear-lanceolate.
Yermo xanthocephalus Yermo xanthocephalus commonly known as the desert yellowhead is an American perennial, endemic to southern Wyoming. It is the only member of the genus Yermo, and was first described in 1991.