funnelform

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Shaped like a funnel, as the corolla of a petunia or a morning glory.

from The Century Dictionary.

• Having the form of a funnel, or inverted hollow cone; specifically, in botany, applied to a monopetalous corolla shaped like a funnel, in which the tube enlarges gradually from below, but expands widely at the summit; infundibuliform.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Bot.) Having the form of a funnel, or tunnel; that is, expanding gradually from the bottom upward, as the corolla of some flowers; infundibuliform.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective having the shape of a funnel