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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where the species may be found. Tetraneuris acaulis var. acaulis range map. USDA PLANTS Database.

Bitterweed (Tetraneuris acaulis</em> var. <em>acaulis) Bitterweed. Photo by Charmaine Delmatier.

A field of bitterweed. Bitterweed habitat. Photo by Charmaine Delmatier.

Bitterweed (Tetraneuris acaulis var. acaulis)

By Charmaine Delmatier (2016)

Bitterweed (Tetraneuris acaulis var. acaulis) is found in the middle interior of both Canada and the United States, from Texas to Alberta and Idaho to the Dakotas. Also known as stemless four-nerve daisy, it is mostly found on gentle hillsides and grasslands, or adjacent to woodlands, it can also be found along roadsides. The Greek derivatives for its scientific name are tetra for four, and neuron for nerve; referring to the four parallel veins running along the corolla of its ray florets.

Known for many years as Hymenoxys acaulis var. acaulis, it has gone through a recent name change with a new treatment by Mark W. Bierner and Billie L. Turner. According to this new treatment, there are nine species of Tetraneuris, and within Tetraneuris acaulis, there are four varieties. Our variety, acaulis, occurs mostly east of the continental divide and generally between 2,300 and 6,500 feet. Depending on local environmental and climatic conditions, it flowers between May and October.

A short hairy perennial and member of the Sunflower family (Asteraceae), its silvery tightly appressed hairs creates a thick fuzzy coat covering on most of the plant. Its height ranges from 4 to 7.8 inches. The spatulate to somewhat linear-leaves can be sparsely to densely covered with glands. The yellow flowering heads are singularly subtended by one to ten individual stems (peduncles). The phyllaries surrounding the flowering head are usually densely hairy.  So with all of these field characteristics, we can envision a very short and fuzzy sunflower on a hairy stem, and that is what you will find.

The sunflower family constitutes the largest plant family in the world with approximately 1,550 genera and 23,000 species. In North America, the numbers are considerably lower with 418 genera and 2,413 species. The orchid family (Orchidaceae) and legume family (Fabaceae) are second and third worldwide. The family, Asteraceae, derives its root from the Greek Titan goddess, Asteria, (goddess of falling stars). According to one Greek myth; when she looked down upon the earth, and saw no stars, she began to weep. Where a tear fell upon the earth, a star was born, hence the name ‘starwort’. This became a common term for members of the Asteraceae family. The term ‘wort’ translates to ‘plant’ in Old English, so the largest plant family in the world is interestingly a collection of ‘starplants’.

Several members of the Asteraceae help sustain the agricultural industry with economically important products such as lettuce, coffee substitutes, herbal teas, sunflower seeds, sunflower oil, and artichokes. Native to central North America, Jerusalem artichoke was used by several North American tribal nations as a food source.  The French explorer, Samuel Champlain, harvested Jerusalem artichoke and transported it to France in 1605. By the mid- 1600s, it also became a source of livestock feed. Ornamentals (grown in plant nurseries) seem unlimited with a ample selection of marigolds, calendulas, cone flowers, zinnias, coreopsis, liatris, various daisies, and prized dahlias.  Once thought an invasive weed, dandelion leaves have become more popular as an accepted salad green on tables across the world. However, this is not a new surprise to many grazing animals; they have already discovered the delicate sweet taste of these fresh leaves.

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