RANGE: Throughout the United States, especially troublesome east of the Mississippi River.
APPEARANCE: Sprawling, thick, fleshy stems with rubbery leaves. Tiny, yellow, five-petaled flowers open when the sun is shining brightly. Cup-shaped seedpods produce many small, black seeds that may lie dormant in the soil for years. Seldom found in the spring when the lawn is treated for other weeds.
GROWTH: Thrives in hot, dry weather, spreading by sprawling stems. It's extremely troublesome in thin areas of the lawn or in new lawns seeded in summer.