Closed gentian, or bottle gentian, is a wildflower of moist prairies. Its flowers never open — they stay closed and budlike throughout the pollination process. It is a smooth, hairless, perennial prairie forb with stems to 2½ feet long, erect or nearly so.
The leaves are opposite, stalkless, and simple, up to 6 inches long, oval to lance-shaped, dark green; upper leaves appear whorled.
Flowers are in dense, terminal clusters, or a few from upper leaf axils, to 1½ inches long, always closed, cylindrical, rather bottle-like. They look like large flower buds. As the flowers mature, their color changes from wine-red through purple to blue. Long-flowering. Blooms August–October.
Missouri has two varieties of closed gentian:
- Var. dakotica is by far the most common variety of closed gentian in Missouri. Its corolla (petal) lobes are broadly triangular and are 1–3 mm (to about 1/8 inch) long.
- Var. andrewsii is uncommon and widely scattered in eastern Missouri, with disjunct populations also in Platte County. Its corolla (petal) lobes are reduced to an inconspicuous point that is no more than 1 mm long. It is listed as a species of conservation concern in Missouri.
Similar species: Several members of the gentian family live in Missouri, including two others in the genus Gentiana: downy gentian, or prairie gentian (G. puberulenta), and pale, white, or yellowish gentian (G. alba). Of the two, G. alba is most similar to closed gentian, though its petals are greenish- to yellowish-tinged instead of blue or purple. At maturity, G. alba’s petal lobes open, but they remain inconspicuous. G. puberulenta, although its flowers are purple and blue, is easily distinguished by its open-spreading petal lobes.
Closed gentian can form hybrids with G. alba; these offspring are called Gentiana x pallidocyanea and have been found in several Missouri counties, mostly in northeastern parts of the state. The corollas are variable but are generally intermediate in color between the two parent types. Look for hybrids wherever the two parent species are growing near each other.
Height: usually 12 to 28 inches.
Scattered nearly statewide. It is rarely abundant.
Habitat and Conservation
Occurs in moist and upland prairies, glades, woodland openings in low and upland woods, streamsides, and below bluffs. Typically associated with moist, low areas and near streams and ponds.
Status
One of Missouri's two varieties of this species, var. andrewsii, is critically imperiled in Missouri and has been listed as a species of conservation concern. The main threat to its survival is loss of habitat — upland prairies and ledges of bluffs.
Human Connections
Closed gentian is a stunning choice for native wildflower gardening, especially in partly shady, moist, well-drained, rich-soil areas. Always get your plants from reputable wildflower nurseries; never dig them from the wild.
Worldwide, the gentian family includes some 80 genera, with more than a thousand species. Many are cultivated as ornamentals or have been used medicinally, especially for digestive upset. The species that are typically used medicinally are European gentians (G. lutea, G. purpurea, G. punctata, and G. pannonica).
Several liqueurs, apéritifs, tonics, and bitters are made with extracts of certain gentian species, usually of roots. You might have heard of Aperol, Suze, Angostura bitters, and Peychaud’s. The root beer–like soft drink Moxie, a favorite soda in New England, also uses bitter gentian root extract as a flavoring. The species most used in beverages is great yellow gentian, G. lutea, a native of Europe.
Ecosystem Connections
The unique flowers of closed gentian permit access only to bumblebees, and the plant and its bees benefit each other. Bumblebees are the principal pollinators, for they alone are large and strong enough to push their way through the tiny opening at the tip. The bees gain exclusive access to a trove of nectar, and the flower, with a pollinator focusing on just its species, has better chances for cross-pollination, and smaller, less-efficient pollinators don't take up its nectar and pollen.
The foliage of gentians is bitter, so the plants are not palatable to most grazing mammals. Because these plants are rarely abundant, they could not form a large part of grazing animals’ diet, anyway.