Overview
The Large Tongue Orchid (Cryptostylis subulata), also affectionately known as the Duckbill Orchid, is an intriguing and robust evergreen terrestrial orchid native to the swampy wetlands and damp coastal heaths of eastern Australia. Unlike the majority of temperate Australian terrestrial orchids that die back to subterranean tubers during the summer dry season, this moisture-loving species maintains lush, leathery evergreen foliage year-round, producing tall spikes of dramatic, inverted blossoms in the heat of summer.
Biology and Physical Characteristics
Cryptostylis subulata grows from an underground cluster of thick, brittle, fleshy roots rather than a round tuber. It produces one to three erect, stiff, leathery, dark green lanceolate leaves standing on long petioles up to twelve inches high, often with purplish underbellies. In mid-summer, a strong, fleshy flowering stem ascends up to nearly three feet, carrying a raceme of up to fifteen upside-down (non-resupinate) flowers. The sepals and petals are reduced to yellowish-green wiry filaments, while the dominating floral feature is the colossal labellum—an elongated, concave, tongue-like channel measuring over an inch long, colored tawny orange-brown with a glistening dark maroon-black central glandular patch.
Behavior and Ecology
The reproductive ecology of Cryptostylis subulata is one of the most famous examples of obligate pseudocopulation in biology. The enlarged tongue-like labellum produces chemical pheromones that mimic the sex pheromone of the female Ichneumon Orchid Wasp (Lissopimpla excelsa). Male wasps are intensely attracted to the flower, landing backward on the elongated lip and attempting to copulate with the decoy. In the process, the wasp presses its abdomen against the base of the column, picking up pollinia on its tail end and transferring them to adjacent flowers during subsequent mating attempts.
Conservation and Human Impact
Classified as Least Concern, the Large Tongue Orchid is abundant in undisturbed peat swamps, tea-tree scrub margins, and national parks across eastern Australia. Because it requires continuously moist soils, the species is vulnerable to wetland drainage, peat mining, and lowered groundwater tables resulting from extended droughts. Protecting coastal wetland hydrology and maintaining natural fire regimes ensure the long-term vitality of its summer blooming populations.
Interesting Factoid
This orchid tricks male ichneumon wasps so convincingly with its perfume and fuzzy tongue that the wasps repeatedly attempt to mate with the flower, transferring pollen with their tails.
Last updated: October 2026