Summary ⁵

Ageratina altissima, or white snakeroot, is a common, widespread plant native to much of eastern North America. The name "snakeroot" refers to a traditional use to cure snakebites. White snakeroot is toxic and when consumed by cattle their milk and meat become contaminated. Consuming these products can cause "milk sickness", which killed thousands of people in the early 19th century including the mother of Abraham Lincoln, Nancy Hanks Lincoln.

At the Garden ⁶

Description ⁷

Perennials, (30–)50–80(–120) cm (bases usually fibrous-rooted crowns, sometimes rhizomatous). Stems ascending to erect, sometimes semiscandent, puberulent (hairs minute, crisped). Leaves opposite; petioles (5–)10–30(–50) mm; blades usually deltate-ovate to ovate or broadly lanceolate, sometimes ovate-lanceolate, 4–11(–13) × 2.5–8(–9) cm, bases usually rounded to truncate or obtuse, sometimes cordate, margins coarsely and doubly incised-serrate, apices usually acuminate. Heads clustered. Peduncles 1–5 mm, puberulent. Involucres 4–5 mm. Phyllaries: apices acute, abaxial faces glabrous or sparsely and finely villous. Corollas white, lobes sparsely short-villous. Cypselae glabrous.

Sources and Credits

1. (c) Ronald Kielb, some rights reserved (CC BY-NC), http://www.flickr.com/photos/53874483@N03/5040978802
2. (c) Jason Whittle, some rights reserved (CC BY-NC-ND), uploaded by Jason Whittle
3. (c) R. A. Nonenmacher, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Ageratina_altissima_SCA-5475.jpg
4. (c) R. A. Nonenmacher, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Ageratina_altissima_SCA-7676%2B77.jpg
5. Adapted by bkmertz from a work by (c) The Preserve at Shaker Village, some rights reserved (CC BY-SA), https://www.inaturalist.org/guide_taxa/523531
6. (c) bkmertz, some rights reserved (CC BY-SA)
7. Adapted by bkmertz from a work by (c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/4954485

More Info

• iNat taxon page
• Biodiversity Heritage Library
• BOLD Systems BIN search
• eFloras.org
• Flora of North America (beta)
• Global Biodiversity Information Facility (GBIF)
• Go Botany
• HOSTS - a Database of the World's Lepidopteran Hostplants
• IPNI (with links to POWO, WFO, and BHL)
• Maryland Biodiversity Project
• NatureServe Explorer 2.0
• New Zealand Plant Conservation Network
• SEINet Symbiota portals
• Tropicos
• USDA PLANTS database
• VASCAN by Canadensys
• World Flora Online
• 日本のレッドデータ検索システム
• 植物和名−学名インデックス YList

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