The flower of Habenaria barbertoni has green sepals and white petals (apart from the sometimes green spur at the back of the lip).
The upper, broader lobes of the lateral petals, about triangular to oblong in shape, adhere to the dorsal sepal to form the hood above. The thin, thread-like lower petal lobes spread and curve in front of the two green lateral sepals that are larger than them and obliquely ovate to oblong in shape.
The three thin lip lobes spreading below are white, longer than the petals; the lateral pair thinner than the midlobe and curving. The column and rostellum arms in the flower centre are starting to lose their whitish colour in the late stage of blooming.
Well below the rest of the flower the long, thin spur protrudes far to its bulging tip, out of this photo, but captured in some of the other photos that are shown (Lowrey and Wright, 1987; Germishuizen and Fabian, 1982; JSTOR).