United States, Illinois, Cook, Techny Railroad, Northbrook; 0.5 mile west of Waukegan Road, south of Techny Road; next to dried pond in middle of remnant prairie.
Immediate edge of dried pond in degraded prairie remnant; abundant; cespitose spike rush growing intermixed with Eleocharis erythropoda; associates: Typha angustifolia, Silphium terebinthinaceum, Juncus species, Carex granularis, Chrysanthemum leucanthemum var. pinnatifidum, Scirpus atrovirens, Rudbeckia hirta, Lobelia spicata.