melancholy thistle(n = noun.plant) cirsium helenioides, cirsium heterophylum - perennial stoloniferous thistle of northern Europe with lanceolate basal leaves and usually solitary heads of reddish-purple flowers;
is a kind of thistle

barnaby's thistle, blessed thistle, blue thistle, boar thistle, brook thistle, bull thistle, canada thistle, carline thistle, common carline thistle, cotton thistle, creeping thistle, european woolly thistle, field thistle, globe thistle, golden thistle, holy thistle, horse thistle, lady's thistle, melancholy, milk thistle, musk thistle, nodding thistle, our lady's mild thistle, plume thistle, plumed thistle, russian thistle, scotch thistle, sow thistle, spear thistle, stemless carline thistle, thistle, welted thistle, white thistle, woolly thistle