| Author | (L.) Mosyakin & Clemants | |
| Distribution | Mostly outer Coastal Plain, where considered native by FNA and by Weakley (2018). Inland records are probably adventive. The range map is very incomplete, owing to the recent split from D. ambrosioides; likely occurs in all coastal counties, based on Weakley's map.
Mostly maritime -- MA to southern FL and southeastern TX; scattered records inland to OH, KS, CA, etc. Mex, W.I., C.A., S.A. | |
| Abundance | Thought to be common in coastal areas. The website editors have offered a vague [S3?] state rank, based on Weakley (2018). | |
| Habitat | Shores of Pamlico Sound (and probably others), stable dune barrens, openings in maritime woodlands. Primarily a species of sandy coastal areas -- dunes, flats, borders of maritime forests and thickets, etc. More details are needed on the separation of habitat vs. the widespread C. ambrosioides. | |
| Phenology | Flowering and fruiting July - November. | |
| Identification | American Wormseed is a much-branched plant generally 1.5-2.5 feet tall, typically covered with glandular resin dots. The lower and middle portions are very leafy, with lance-shaped to narrowly ovate leaves, the margins varying from straight-cut to toothed to sinuous lobed. The inflorescences are produced terminally and on branches, composed of small clusters of roundish fruits. It is very similar to the more common and alien Mexican-tea (C. ambrosioides), but that plant has well-developed leafy bracts (vs. tiny and barely noticeable in this species). This distinction should be obvious in the field -- as Mexican-tea has distinct "leaves" embedded within the inflorescence and American Wormseed is "leafless" amid the flower clusters. | |
| Taxonomic Comments | Note that D. anthelmintica has been recently split out of D. ambrosioides.
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| Other Common Name(s) | Wormseed. Usually just called this name, but the "American" is added to show that this species is native to the Atlantic coast. | |
| State Rank | [S3?] | |
| Global Rank | GNR | |
| State Status | | |
| US Status | | |
| USACE-agcp | | |
| USACE-emp | | |
