A Thief in the Undergrowth
The Crested Coralroot, Hexalectris spicata, is an orchid that has abandoned photosynthesis entirely. It produces no leaves and contains no chlorophyll, the green pigment that allows most plants to create their own food. Instead, it lives as a mycoheterotroph, a plant that steals nutrients from fungi. This orchid targets the vast underground networks of mycorrhizal fungi that live in a symbiotic relationship with trees, particularly oaks. The orchid's thick, branching rhizomes, which resemble coral, tap into the fungal network, siphoning sugars and nutrients that the fungi have acquired from their host trees. This makes the orchid a parasite on a fungus that is otherwise helping a tree.
The plant spends most of its life as this unseen rhizome system, often for many years at a time. Its appearance above ground is unpredictable; some years a population may produce a profusion of flowering stalks, while in other years none appear at all. Botanists believe that heavy summer rains may encourage blooming, but the exact environmental triggers for this synchronized emergence are not fully understood. Because most of the plant's life happens underground, assessing the health or size of a population is very difficult.
Ephemeral Flowers, Hidden Life
When Hexalectris spicata does emerge, it sends up a leafless stalk that can range from 15 to 90 centimeters (6 to 35 inches) tall. The stem itself is typically a yellowish-brown, sometimes with pink or purple tones, and is easily missed against the forest floor's leaf litter. The stalk carries a raceme of 8 to 25 flowers. Each flower, about 2.5 centimeters (1 inch) wide, is colorful. The sepals and two of the petals are typically golden-brown or yellow, with purplish-brown stripes.
The flower's most distinctive feature is its lower petal, or lip. This lip is typically white or pale and features five to seven purple ridges or crests. This structure gives the orchid its name; Hexalectris comes from Greek for "six" and "rooster," referring to the ridges that resemble a rooster's comb. The species name spicata simply refers to the flowers being borne on a spike. This orchid is native to a wide range of the eastern and southwestern United States and Mexico, typically found in the dry, well-drained soils of upland oak woodlands.