Above this belt the firs gradually disappear and are succeeded by the shortleaved Pinus montezumae, or Mexican " ocote " - one of the largest species of pine in the republic. These continue to the upper tree-line, accompanied by red and purple Pentstemon and light blue lupins in the open spaces, some ferns, and occasional masses of alpine flowers.
In Scrophularia the fifth stamen appears as a scale-like body; in other Scrophulariaceae, as in Pentstemon, it assumes the form of a filament, with hairs at its apex in place of an anther.
American plants nearly allied to Pentstemon, the species in cultivation are handsome border plants, flowering in late summer and in autumn.