Mountain bugbane is primarily an East Coast native, but it's also found in Illinois (though it's currently on the endangered list here). Its white bottlebrush blooms rise 5 yo 6 feet above the mound of ferny deeply cut foliage in late summer - a regal sight in the open shade of deciduous woods.

There are over 35 different species of bugbane or Actaea,
spanning Europe, Asia, and North America. They're generally woodland
plants, happiest in dappled shade and cool, consistently moist soil.
Most form mounds of toothed leaves and then in mid-summer send up spikes
of tightly packed flowers, often followed by conspicuous berries. NOTE:
Berries are poisonous to people and rabbits; harmless to birds and
butterflies.