white top
/ˈwʌɪt ˌtɒp/adjective
1Designating a turnip root having a white top, and varieties of turnip producing such roots.
2Of a plant: having upper parts (typically flowers or foliage) that are white or very pale.
noun
1Any of various grasses having a pale inflorescence.
2Any of several eucalyptus trees, especially the blackbutt, Eucalyptus pilularis, the bark of which peels from the upper trunk, leaving a whitish surface.
3 US. Any of various plants regarded as weeds of agricultural land, especially any of several white-flowered species of fleabane (genus Erigeron), and hoary cress, Lepidium draba.
Origin
Late 18th century. From white + top.