calla lily

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

• noun Any of several southern African plants of the genus Zantedeschia, widely cultivated as ornamentals and cut flowers for their showy white, yellow, pink, or purple spathes.

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

• noun A common name for certain flowering plants in the genus Zantedeschia; not related to either the genus Calla or the true lilies (Liliaceae)
• noun A flower of one of these plants.

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

• noun South African plant widely cultivated for its showy pure white spathe and yellow spadix