ClipArt ETC
A corolla with a regularly expanding tube.

Funnel-Shaped Corolla

A corolla with a regularly expanding tube.

"In botany, applied to a monopetalous corolla shaped like a funnel, in which the tube enlarges gradually from below, it expands widely at the summit; infundibuliform." -Whitney, 1911

Funnelform Corolla

"In botany, applied to a monopetalous corolla shaped like a funnel, in which the tube enlarges gradually…