Cup plant is in the flowering plant family Asteraceae - the daisy or aster family. The Asteraceae is the second-largest family of flowering plants world-wide and there are many species native to southern Ontario. Cup plant is spectacular because it is a very large perennial wildflower; the stems reach a height of 6 feet or more. It also has beautiful large leaves, and is so-named because of an interesting feature of the leaves. The base of the leaves wrap around the stem and form a cup that can temporarily hold a small amount of water.
Close-up of cup plant leaf bases holding water, spring 2011 (photo NMZ)
Cup plant's beautiful spring foliage, 2011 (photo NMZ)
Cup plant mature flowers in early August 2010 (photo NMZ)
Native bee on cup plant, late July 2011 (photo NMZ)