NATURAL HISTORY

WHITE FRINGELESS ORCHID } Platanthera integrilabia (Correll) Luer

FAMILY: Orchidaceae

DESCRIPTION: The white fringeless orchid is a perennial herb with a vertical stem that grows to about 2 feet tall. It has a thin, light green stem rising from a tuber, and its leaves have smooth edges and tend to be long and narrow, with leaves lower on the plant being larger than leaves higher up. The plant has white flowers that collect in a loose cluster at the end of the stem.

HABITAT: This orchid grows in the wet soils of bogs, marshes, fens, swamps, heads of streams, and on sloping areas kept moist by groundwater seeping to the surface. It is often associated with sphagnum in partially shaded areas.

RANGE: Currently found in Georgia, Alabama, Mississippi, South Carolina, Tennessee and Kentucky, the species has been extirpated from North Carolina.

LIFE CYCLE: The white fringeless orchid flowers from late July through September. It is pollinated by butterflies, including eastern tiger swallowtails, spicebush swallowtails and silver-spotted skippers, whose long tongues are adapted to probe the long, nectar-containing spur of the orchid. During the probing process, packets of pollen stick to the front of the butterflies' heads and are brushed off onto the stigmas of flowers that the butterflies subsequently visit. Flowers must be cross-pollinated for fruit to set. Seeds are also dispersed by wind and gravity.

THREATS: The species is threatened by logging, off-road vehicles, development, canopy closure, drought, overbrowsing by deer, digging by feral hogs, ditching and draining of wetlands, herbicide spraying, pollution and sedimentation into streams, and invasion by exotic pest plants.

POPULATION TREND: Historically there were at least 90 populations of the white fringeless orchid. Now its status is uncertain in more than one-third of the 58 small populations where it remains in Alabama, Georgia, Kentucky, Mississippi, South Carolina and Tennessee. The species has completely disappeared from North Carolina.

Photo by Brad Wilson