Jim Brandenburg / Temperate forest interior with trillium ground cover, Northwoods, Minnesota

Jaymi Heimbuch / Pacific Trillium (Trillium ovatum) flower, Big Creek Park, Newport, Oregon

Steve Gettle / Large-flowered Trillium (Trillium grandiflorum) flower, North America

Steve Gettle / Dwarf Crested Iris (Iris cristata) and trillium on forest floor, Great Smoky Mountains National Park, Tennessee

Michael Durham / Pacific Trillium (Trillium ovatum) blooming in early spring, Oregon

Michael Durham / Pacific Trillium (Trillium ovatum) flower cross section showing the long stem, subterranean bulb and roots, Oregon

Kevin Schafer / Pacific Trillium (Trillium ovatum) flower, Oregon

Albert Aanensen / Trillium flower {Trillium sp} USA

Jaymi Heimbuch / Pacific Trillium (Trillium ovatum) flower, Big Creek Park, Newport, Oregon

Jaymi Heimbuch / Purple Trillium (Trillium erectum) flowering, Butano State Park, California

Steve Gettle / Large-flowered Trillium (Trillium grandiflorum), Great Smoky Mountains National Park, Tennessee

Steve Gettle / Large-flowered Trillium (Trillium grandiflorum), Great Smoky Mountains National Park, Tennessee