THIMBLEWEED
thimbleweed, Anemone cylindrica
(noun) a common North American anemone with cylindrical fruit clusters resembling thimbles
Source: WordNet® 3.1
Etymology
Noun
thimbleweed (plural thimbleweeds)
Any of various plants whose heads resemble thimbles, including
Rudbeckia laciniata
Anemone virginiana
Anemone cylindrica
Source: Wiktionary
Thim"ble*weed`, n. (Bot.)
Definition: Any plant of the composite genus Rudbeckia, coarse herbs
somewhat resembling the sunflower; -- so called from their conical
receptacles.
Source: Webster’s Unabridged Dictionary 1913 Edition