About Grindelia squarrosa (Pursh) Dunal
Grindelia squarrosa, also called curlycup gumweed, is an erect, branched biennial or perennial herb or subshrub that typically grows 40 to 100 cm tall. Its leaves are 1.5–7.5 cm (1⁄2–3 inches) long, gray-green, resinous, and crenate, with each tooth bearing a yellow bump near its tip. The plant produces numerous flower heads arranged in open, branching clusters. The flower bract (involucre) is moderately to strongly resinous, and made up of multiple overlapping rows of phyllaries. The tips of these phyllaries curl strongly outward, are hooked or looped, and sometimes curl back to form a circle. Each flower head usually holds 12–40 yellow ray flowers, though ray flowers are sometimes absent; the ray flowers surround many small disc flowers. Bloom time occurs from July through late September. The plant's brown seeds are usually four-angled, with loose scales. Grindelia squarrosa is native to western and central North America, ranging from British Columbia east to Québec and New England, and south to California, New Mexico, Arizona, Chihuahua, and Texas. It may possibly be naturalized across much of the eastern part of this native range, and has been introduced to Asia in Ukraine. It most often grows in dry, open areas, as well as disturbed roadsides and streamsides, at elevations between 700 metres (2,300 feet) and 2,300 metres (7,500 feet). While sage grouse chicks have been reported to eat this plant, its content of tannins, volatile oils, resins, bitter alkaloids, and glucosides give it an unpleasant taste to most wildlife. The Lady Bird Johnson Wildflower Center Native Plant Information Network lists the species as having special value to native bees. Due to its weedy growth habit, it often volunteers to grow in disturbed areas on its own; it has been tested for seeding disturbed roadsides in Wisconsin, where it produced good results under adverse growing conditions. The plant concentrates selenium from the soil, so it can be toxic if ingested by cattle, humans, and other mammals. However, it is rarely eaten because of its unpleasant taste. Since it is not very palatable to livestock, it becomes more abundant in overgrazed areas, and can have a negative impact on grazing ranges. It can also act as an indicator of poor range management, because other plant species can usually compete with it and slow its spread if they are allowed to grow undisturbed. Great Plains Tribes use the flowers and leaves of this plant as a medicinal herb to treat conditions including asthma, bronchitis, and skin rashes. Powdered flowers were once smoked in cigarettes to ease asthma symptoms. It is used as a traditional medicinal plant by Shoshone peoples in various regions. It is called mu’-ha-kûm in the Gosiute language, and pteíčhiyuȟa in the Lakota language. Hispanos of New Mexico boil the buds to make a drink to treat kidney disorders. Plant extracts have been used to treat skin irritations, asthma, and rheumatism, and the resin has been applied topically to treat poison ivy rashes. Grindelia squarrosa is currently being explored as a potential source of biofuel, because it has a high content of mono- and di-terpenes that can be converted into a fuel similar to kerosene or jet fuel. Its adaptation to arid climates makes it an attractive option for this purpose, as growing it in desert areas would not compete with cultivation of traditional food crops.
