Thelesperma megapotamicum (Spreng.) Kuntze

by Shalene Yazzie, Native Plants of Arizona 2009
Common names: Hopi tea greenthread, Navajo tea (1).
Family: Asteraceae.
Synonymy : Bidens megapotamica Spreng, Thelesperma gracile (Torr.) A. Gray (1)
Etymology: Specific epithet meaning “of the large river” from the Latin mega meaning large, and potam referring to river(2).

Growth form: Forb/ herb with slender, delicate stems (3).
Stem: Long, willowy, and branched to 0.3-.6m tall (1).
Leaves: Opposite, usually pinnately lobed into tapered linear segments (4).
Inflorescence/flowers: Small to medium sized heads, appearing either golden or brown (4). Lobes of the disk corollas are linear-lanceolate (4).
Fruit: Achene usually papillate, shaped oblong (almost linear), with the pappus of two triangular hispid teeth (4).
Similar species: T. megapotamicum can be distinguished from the two other Thelesperma species by the thick inflorescence disk head (1-1.5 cm wide), with the outer phyllaries very short and rounded. Also the lobes of the disk corollas are longer than the throat (4).

Life history: Perennial forb (3).
Native/introduced: Native (1).
Phenology: Flowers April/May-October (5).
Distribution: Open pine forests to grasslands and deserts, from 4,000-7,500 ft. (6). In Arizona , T. megapotamicum is found in Yavapai, Coconino, Navajo, Apache, Pinal, Pima, Graham, Santa Cruz , and Cochise counties (1). Also found in the lower 48 United States (1).

Ethnobotany/Uses:Medicinal uses for T. megapotamicum are from the ethno botanical uses derived from Native American tribes. The flowers, stems and leaves are used in teas to treat many ailments including tuberculosis, toothaches, and as a stimulating and aromatic drink (7). The Hopi and Navajo also used the flowers and leaves as a brown dye for textiles and basketry (6).

1. USDA, NRCS. (2009) The PLANTS Database. Retrieved Oct. 12, 2009 .
2. Gledhill, David. Names of Plants.West Nyack , NY , USA : Cambridge University Press, 2002.
3. Southwest Environmental Information Network. Thelesperma megapotamicum. In SEInet. (Retrieved October 16, 2009 )
4. Kearney , Thomas, and Robert Peebles. Arizona Flora . 2nd. Berkeley and Los Angeles : University of California Press, 1964. Print. (pg. 908-909)
5. Kuntze, Revis. "Thelesperma megapotamicum. " Flora of North America ., Web. 17 Oct 2009 . <>.
6. Epple, Anne. A Field Guide to the Plants of Arizona . 1st. Helena , Montana : Falcon Press Publishing Company, 1995.
7. Moerman, Dan. "Thelesperma megapotamicum." Native American Ethnobotany . University of Michigan-Dearborn, Web. 18 Oct 2009 . <>.