The 32 acre Crosby Oxypolis Heritage Preserve in Colleton County was acquired to protect a population of the federally-endangered plant Canby's dropwort (Oxypolis canbyi), also known as Cowbane. At the time the preserve was protected, only five populations of this plant were known to exist. Since that time, at least fourteen other populations from Delaware to Georgia have been documented. Canby's dropwort is a herbaceous perennial that grows from 3-6 feet tall. The stems are slender and vary in color from purple to green, depending on their location on the plant. The flowers are axillary, compound umbels that are white. Blooming usually occurs in August or September. Canby's dropwort prefers permanently flooded bays or wet pine savannahs with little or no overstory. The soils are typically sandy loam with an underlying clay layer that perches the water table. The soils are usually poorly drained, acidic and high in organic matter. The most serious threat to this species is the destruction or alteration of wetlands. This might take the form of conversion to pine plantations or pasture, water table alteration by roads or ditches, or clearing for development.