Southern plains trout lilies have grown through the leaf litter despite twenty-degree temperatures at night. They'll poke through snow too, if we have it. Their green leaves are darkly blotched with purplish brown, like a trout, and they're hard to see unless accompanied by dainty white blooms with recurved petals that remind me of Easter lilies. Today is sunny, a must for finding trout lilies, because their flowers close in cloudy weather and at night -- by about 6:30 p.m. under clear skies at their peak on Valentine's Day. Petals turn pink as they age, and by mid-March solid green leaves accompany green seed pods. By the time of tree-canopy shade in mid-April, trout lilies retreat underground again. Five inches deep, where temperatures are twenty degrees higher, the lilies have a corm (like a bulb) that produces small offsets that break away and grow into single-leaf plants. That's why the species lives in tight colonies. Annually, leaves come up larger than the year before, as each year's leaves feed corms that store more food energy that produces more leaf machinery. After about five good growing years two leaves emerge and a year or two later the single flower appears. The year after that I find only one or two leaves again, because flowering requires extra energy. My marked plants have lived eighteen years so far, blooming off and on, balancing their flower-cost: leaf-benefit ratio. Trout lily colonies are patchily distributed, possibly because first Americans ate the corms and carried them from camp to camp, occasionally dropping some (humans aren't native to the Americas but some arrived about twelve thousand years before the rest of us). Comparing modern human impacts on the patches of lilies, I walk from those grazed by cattle to others overrun by Japanese honeysuckle or cut by mountain bike and foot trails, and find progressively more blooms. Yet even the least disturbed lilies are sparser than elsewhere, probably because they are naturally stressed here near their southern margin of range.