snail-flower

from The Century Dictionary.

• noun A twining bean, Phaseolus Caracalla, often cultivated in tropical gardens and in greenhouses for its showy white and purple fragrant flowers. The standard and the long-beaked keel are spirally coiled, suggesting the name.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun perennial tropical American vine cultivated for its racemes of showy yellow and purple flowers having the corolla keel coiled like a snail shell; sometimes placed in genus Phaseolus