oxalis genus --- woodsorrel family
alpine woodsorrel (Oxalis alpina) -- in July -- Sandia Peak, Cibola National Forest, southern New Mexico red & pink
slender yellow woodsorrel (Oxalis dillenii) -- in August -- Well Gulch Nature Trail, Lory State Park, CO yellow & orange
slender yellow woodsorrel (Oxalis dillenii) -- in June -- Viewpoint Trail, Pineridge, Fort Collins Natural Area, CO
redwood sorrel (Oxalis oregana) -- in April -- Columbia River Gorge, northern Oregon white & cream
yellow woodsorrel (Oxalis stricta) -- in April -- Great Smoky Mountains National Park, TN yellow & orange
violet wood sorrel (Oxalis violace) -- in April -- J.T. Nickel Nature Preserve, northern Oklahoma blue & purple