winter aconite

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

• noun Any of various Eurasian herbs of the genus Eranthis of the buttercup family, especially E. hyemalis, having palmately dissected leaves and a solitary yellow flower that blooms in winter or early spring.

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

• noun small Old World perennial herb grown for its bright yellow flowers which appear in early spring often before snow is gone