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 Idaho Mountain Wildflowers

The Gentian Family, Gentianaceae

Gentianaceae: The Gentian Family. Gentians are the aristocrats of alpine flowers.Many are an intense blue color. They grow in moist, rich soil deposited by slow flowing streams, along the shores of mountain lakes and in wet mountain meadows. Tolerant to cold, gentians may continue to bloom even when the nights are freezing; as they are low to the ground and sheltered by sun-warmed earth. Gentians have been gentians for more than two millenia. King Gentius, in the second century BC, ruled Illyria, a Balkan country located in what is now Yugoslavia.. The king believed that the roots of a certain flowering plant had medicinal value. He was wrong, but the plant has been associated with his name ever since, and so we have “Gentian” today. The family is made up of 60 or so genera and about 800 species. Most are found in the north temperate zone; a half dozen or so are cultivated as ornamental plants.
Pleated gentian, Gentiana affinis Griseb. (left). The pleated gentian takes its common name from an inward folding membrane that joins one petal to the next. As in this plant, the petals often have a reticulated pattern of greenish spots on their upper surfaces. Pleated gentians spread by sending out roots, and are often found growing in clusters that sometimes suggest the “fairy rings” formed by proliferating field mushrooms. Each of the pleated gentian’s stems bears several pairs of small, opposite, lanceolate leaves and a terminal flower. As with other members of this genus, this gentian prefers moist montane meadows and the banks of lakes and streams.

Explorer’s gentian, Gentiana calycosa Griseb. (right). The explorer’s gentian (known also as the the mountain gentian or bog gentian) is the largest, showiest, highest, and latest blooming of our gentians. It grows close to treeline, in moist subalpine meadows and on the loamy banks of slow-flowing streams. It sometimes blooms into September, accompanied only by lingering asters and the ubiquitous yarrow. Its flowers are five-petaled, speckled inside and, like the plant shown above, have a “pleat” connecting the petals. The leaves tend to be wider than those of our other Gentiana. Its species name, calycosa, from the Latin word for “calyx,” refers in this case to the cup-shaped flowers.

One-flowered gentian, Gentianopsis simplex (A. Gray) Iltis (left). The one-flowered gentian has a small and—as its name suggests—a plain flower, noticeable mostly for its intense blue color. Until recently classified in genus Gentiana, it is now in Gentianopsis, a genus made up of similar four-petaled gentians. It is a close relative of the Rocky Mountain fringed gentian (Gentianopsis thermalis [Kuntze] Iltis., not shown), a plant that also grows in Idaho. Both have four petals, but this one usually has little, if any, fringing at the end of the petals. Both plants grow along streams, and in moist high montane to subalpine meadows, blooming from mid-July through August. The ending of the generic name, -opsis, is derived from the Greek word for “view” or “looks like,” thus “a plant that looks like (or is similar to) a gentian.”

Autumn dwarf-gentian, Gentianella amarella (L.) Boerner (right). This is the daintiest of our Gentianaceae. It flowers during the second half of August in moist, high montane to subalpine meadows. With minor differences, the same plant ranges across North America, Europe and Asia. Our plants are pink, but in other places they may be off-white or even pale yellow. They may be identified by the fringe of fine hairs inside the petals—shown here in a magnified view. The species name amarella means “a little bitter.”

Swertia, Swertia perennis L. (left, right). The swertia (also felwort or star gentian) is the only member of its genus found in America. It is a late-blooming circumboreal plant that grows in all of the western states, in British Columbia, and in Eurasia. The plant favors wet montane to subalpine meadows. Its four petals range in color from light purple to almost black, each petal has two nectar pits at its base. The fruiting capsule is quite prominent. Emanuel Sweert (1552-1612), was a Dutch botanist who composed a catalog of plants.

Clustered elkweed, Frasera fastigiata (Pursh) A. Heller (left). The clustered elkweed is found in North-central Idaho (reported from Idaho, Latah, Lewis and Benewah counties) and in the nearby Blue Mountains of Oregon and Washington. It is a tall, large-leaved plant topped with four-petaled blue flowers. It is the only member of the gentian family that Meriwether Lewis collecte, June 14th, 1806 on the Weippe Prairie. The name, fastigiata, implies “cone-like” for the shape of the flower cluster.

White gentian, Frasera montana Mulford (right). The white gentian grows in central Idaho, north of Galena Summit (US Highway 75) in Custer county, west to Boise county. A high montane plant, it blooms in late spring on dry ground, usually in the company of sagebrush. Four- petaled, clustered flowers and white bordered, narrow leaves serve to identify it.

Monument plant, Frasera speciosa Douglas ex Griseb. (left, right), The monument plant (giant frasera, green gentian) is a tall, narrow, cone-shaped plant with flowers clustered around the upper part of its stem. The plants live for many years, but bloom only once and then die. Flowering is unpredictable, but seems related to moisture. The flowers are about 3/4'' diameter with a long sepal visible between each of its four purple-spotted petals. Each petal has two pits at its base and four stamens that surround a one-seed ovary. The plants, formerly pretty much confined to valley floors, now grow as high as treeline. The name Frasera honors John Fraser, (1750-1811), a Scots nurseryman who collected in southeastern North America. The name speciosa means “showy.”

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