Overview

Comprehensive Description

Description

This perennial plant is about 1½–3' tall, branching occasionally. The light green to tan stems are terete and hairless (or nearly so). The opposite leaves are up to 5" long and 3½" across, becoming smaller as they ascend the stems. The lower leaves are cordate to cordate-ovate, while the upper leaves are broadly lanceolate to lanceolate. All of the leaves are largely hairless and strongly serrated-crenate along their margins; they are medium to dark green on their upper surfaces and light green on their lower surfaces. There are 3 prominent veins on the upper surface of each leaf (particularly the lower ones), while the lower surface has an elevated network of veins. The rather long petioles are ½–2½" in length. The upper stems terminate in compound corymbs or flat-headed panicles of flowerheads that span 2-6" across. The branches of this inflorescence are light green and glabrous (or nearly so). Each flowerhead is about ½" across and contains 10-30 disk florets that have brilliant white corollas and styles. There are no ray florets. Each disk floret is about 3-5 mm. across when it is fully open, consisting of a small tubular corolla with 5 lobes that are spreading and pointed and a divided style that is strongly exerted from the corolla. At the base of each flowerhead, there is a single series of linear floral bracts that are light green and non-overlapping. The blooming period occurs from late summer through the fall, lasting about 2 months for a colony of plants. This is one of the last wildflowers to bloom during the fall. The flowers are often fragrant. During autumn, each disk floret in a flowerhead is replaced by an achene with a small tuft of white hairs. These achenes are 2-3 mm. long, narrowly oblongoid in shape, 5-ribbed, and black; they are distributed by the wind. The root system consists of spreading rhizomes and shallow fibrous roots. This plant can spread vegetatively by means of its rhizomes, or it can reseed itself into new areas.
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Palynology

Ageratina altissima pollen has tricolporate apertures with echinate ornamentation. (Jones & Wilson, 2001.)

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General Description

Ageratina altissima was first described as Ageratum altissimum by Linnaeus in Species Plantarum, Vol. 2, in 1753. In 1970, R.M. King and H. Robinson reviewed the classification and renamed it under the epithet Ageratina altissima with two varieties, var. altissima and var. roanensis.

A. altissima is a perennial herb with an upright stem and clustered, white flower heads. Var. roanensis, known as the Appalachian white snakeroot, has slightly longer phyllaries with cuspidated apices. Its growth is mostly limited to the southeastern U.S. Var. altissima grows throughout the entire eastern U.S. and southeastern Canada.

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Distribution

National Distribution

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

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As a species, Ageratina altissima spans the entirety of the eastern and midwestern United States, in addition to the corresponding southcentral to southeastern parts of Canada. A. altissima var. altissima is found throughout the entire range, with the exclusion of Georgia. A. altissima var. roanensis is isolated to the southeastern U.S. excluding coasts. (Nesom, 2006.)

For more information, see the maps above provided by Flora of North America.

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Physical Description

Morphology

The key to the varieties below is taken from Flora of North America. (Nesom, 2006.)

1. Phyllaries 3-5 mm, apices not cuspidate..............................................1a. Ageratina altissima var. altissima

1. Phyllaries 4-7 mm, apices cuspidate to acuminate.............................1b. Ageratina altissima var. roanensis

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Description

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.
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Diagnostic Description

Synonym

Ageratum altissimum Linnaeus, Sp. Pl. 2: 839. 1753, not Eupatorium altissimum Linnaeus 1753
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"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."

Nesom, Guy Ageratina" in Flora of North America, Vol. 21, p. 547-553. Oxford University Press, Inc., New York, NY. 2006.

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Type Information

Isotype; Isotype for Eupatorium deltoides E.L. Braun, nom. illeg.
Catalog Number: US 2663025
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): E. L. Braun
Year Collected: 1939
Locality: Tunnel Rock, Cumberland Falls., Whitley, Kentucky, United States, North America
  • Isotype: Braun, E. L. 1940. Rhodora. 42: 50.; Isotype: Fernald, M. L. 1942. Rhodora. 44: 463.
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Isotype; Isotype for Eupatorium deltoides E.L. Braun, nom. illeg.
Catalog Number: US 1785222
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): E. L. Braun
Year Collected: 1939
Locality: Tunnel Rock, Cumberland Falls., Whitley, Kentucky, United States, North America
  • Isotype: Braun, E. L. 1940. Rhodora. 42: 50.; Isotype: Fernald, M. L. 1942. Rhodora. 44: 463.
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Isotype; Isotype for Eupatorium deltoides E.L. Braun, nom. illeg.
Catalog Number: US 2663031
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): E. L. Braun
Year Collected: 1939
Locality: Tunnel Rock, Cumberland Falls., Whitley, Kentucky, United States, North America
  • Isotype: Braun, E. L. 1940. Rhodora. 42: 50.; Isotype: Fernald, M. L. 1942. Rhodora. 44: 463.
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Ecology

Habitat

Both varieties of Ageratina altissima thrive in moist cove forests. Var. altissima is found at an altitude of 10-800 m, whereas var. roanensis prefers a higher altitude between 700-1500 m. (Nesom, 2006.)

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Dispersal

Like other composites, its fruit is an achene and it is dispersed with the help of the wind.

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Associations

Flower-Visiting Insects of White Snakeroot in Illinois

Ageratina altissima (White Snakeroot)
(Also called Eupatorium rugosum; bees suck nectar or collect pollen, flies suck nectar or feed on pollen, other insects suck nectar; some observations are from Graenicher as indicated below, otherwise they are from Robertson)

Bees (long-tongued)
Apidae (Apinae): Apis mellifera sn cp fq (Rb, Gr); Apidae (Bombini): Bombus griseocallis sn (Gr), Bombus vagans sn cp (Gr); Anthophoridae (Ceratinini): Ceratina dupla dupla sn (Gr); Megachilidae (Megachilini): Megachile centuncularis sn cp (Gr), Megachile latimanus sn cp (Rb, Gr), Megachile mendica sn cp (Rb, Gr)

Bees (short-tongued)
Halictidae (Halictinae): Agapostemon sericea sn (Gr), Augochlorella striata sn, Halictus (or Lasioglossum) sp. sn cp (Gr), Halictus confusus sn cp (Rb, Gr), Halictus ligatus sn cp fq, Lasioglossum coriaceus sn (Gr), Lasioglossum imitatus sn, Lasioglossum versatus sn cp (Gr), Lasioglossum zephyrus sn cp (Gr); Colletidae (Colletinae): Colletes compactus sn (Gr)

Wasps
Sphecidae (Larrinae): Ancistromma distincta; Sphecidae (Sphecinae): Sphex ichneumonea (Gr); Scoliidae: Scolia bicincta (Rb, Gr); Vespidae: Dolichovespula maculata, Vespula germanica; Vespidae (Eumeninae): Ancistrocerus adiabatus (Rb, Gr)

Flies
Culicidae: Aedes vexans (Gr); Scathophagidae: Scathophaga furcata (Gr); Syrphidae: Allograpta obliqua sn (Rb, Gr), Eristalis arbustorum (Gr), Eristalis brousii (Gr), Eristalis dimidiatus (Gr), Eristalis tenax (Gr), Eristalis transversus (Gr), Helophilus fasciatus (Gr), Paragus tibialis (Gr), Rhingia nasica, Spilomyia fusca (Gr), Spilomyia longicornis sn (Rb, Gr), Syritta pipiens (Gr), Syrphus ribesii sn (Rb, Gr), Toxomerus geminatus (Gr), Tropidia quadrata (Gr); Bombyliidae: Anthrax oedipus (Gr), Exoprosopa fasciata sn, Sparnopolius confusus (Gr); Tachinidae: Archytas analis (Gr), Estheria abdominalis sn, Gymnoclytia immaculata (Gr), Gymnoclytia occidua sn, Gymnosoma fuliginosum (Gr), Paradidyma singularis sn, Phyllomya cremides (Gr); Anthomyiidae: Delia platura (Gr); Calliphoridae: Lucilia illustris (Gr), Lucilia sericata (Gr); Muscidae: Graphomya maculata (Gr), Musca domestica (Gr), Neomyia cornicina sn, Stomoxys calcitrans (Gr)

Butterflies
Nymphalidae: Limenitis archippus (Gr), Phyciodes tharos (Gr), Speyeria aphrodite aphrodite (Gr); Lycaenidae: Celastrina argiolus

Skippers
Hesperiidae: Ancyloxypha numitor (Gr)

Moths
Ctenuchidae: Cisseps fulvicollis; Noctuidae: Anagrapha falcifera (Gr); Tortricidae: Grapholita interstinctana (Gr)

Beetles
Chrysomelidae: Acalymma vittata (Gr), Epitrix cucumeris (Gr); Curculionidae: Hypera punctata (Gr)

Plant Bugs
Miridae: Lygus lineolaris (Gr), Plagiognathus sp. (Gr)

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Ageratina altissima has nectar that attracts a variety of moths, butterflies, wasps, flies and bees. Some caterpillars may feed on its foliage. Mammals usually avoid it due to the bitter taste of the toxic compounds within.

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Life History and Behavior

Life Cycle

Phenology

Both varieties can be found flowering late summer, July to October.

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Perennial

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Physiology and Cell Biology

Physiology

Chemistry

Recent studies indicate that there may be three distinct chemotypes of Ageratina altissima. In addition to tremetol, six previously unrecorded compounds of varying toxicity have been found in an extract from the plant. It is thought that this variation could be responsible for the sporadic poisoning associated with A. altissima. (Lee et. al., 2010)

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Cell Biology

Cytology

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Ageratina altissima

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 2
Species With Barcodes: 1
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Conservation

Conservation Status

National NatureServe Conservation Status

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

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NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

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Relevance to Humans and Ecosystems

Benefits

Cultivation

The preference is partial sun to light shade, moist to slightly dry conditions, and soil containing loam or clay-loam. Full sun in a dry situation can cause the leaves to turn yellow and wilt, otherwise this plant is easy to grow. Range & Habitat
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Risks

Risk Statement

Occasionally large mammals will try it, resulting in illness or death. Consequently, humans who consume the milk of an animal that has eaten A. altissima can also get sick and die.

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Wikipedia

Ageratina altissima

For other uses, see Ayapana triplinervis.

Ageratina altissima, also known as white snakeroot,[2] richweed,[2] white sanicle,[citation needed] or tall boneset,[citation needed] is a poisonous perennial herb in the family Asteraceae, native to eastern North America. An older binomial name for this species was Eupatorium rugosum, but the genus Eupatorium has undergone taxonomic revision by botanists and a number of the species once included there have been moved to other genera.

Plants are upright or sometimes ascending, growing to 1.5 meters tall, producing single or multi-stemmed clumps. They are found in woods and brush thickets where they bloom mid to late summer or fall. The flowers are a clean white color and after blooming, small seeds with fluffy white tails are released to blow in the wind. This species is adaptive to different growing conditions and can be found in open shady areas with open bare ground; it can be weedy in shady landscapes and in hedgerows. There are two different varieties Ageratina altissima var. angustata and Ageratina altissima var. roanensis (Appalachian white snakeroot); they differ in the length of the flower phyllaries and shape of the apices.[3][4]

Toxicity[edit]

See also: Milk sickness

White Snakeroot contains the toxin tremetol; when the plants are consumed by cattle, the meat and milk become contaminated with the toxin. When milk or meat containing the toxin is consumed, the poison is passed on to humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans. The poisoning is also called milk sickness, as humans often ingested the toxin by drinking the milk of cows that had eaten snakeroot.

During the early 19th century, when large numbers of European Americans from the East, who were unfamiliar with snakeroot, began settling in the plant's habitat of the Midwest and Upper South, many thousands were killed by milk sickness. Notably, milk sickness was possibly the cause of death in 1818 of Nancy Hanks Lincoln, mother of Abraham Lincoln.[5]

It was some decades before European Americans traced the cause to snakeroot, although today Dr. Anna Pierce Hobbs Bixby is credited with identifying the plant in the 1830s. Legend has it that she was taught about the plant's properties by a Shawnee woman.[6][7] The Shawnee woman's name is lost to history, but she and her people would have had deep knowledge of the herbs and plants in the area.

The plants are also poisonous to horses, goats, and sheep. Signs of poisoning in these animals include depression and lethargy, placement of hind feet close together (horses, goats, cattle) or held far apart (sheep), nasal discharge, excessive salivation, arched body posture, and rapid or difficult breathing.

Inflorescences

This plant does serve a medical purpose. Root tea has been used to treat ague, diarrhea, kidney stones, and fever. A root poultice can be used on snakebites.[8]

Cultivation[edit]

A cultivar, sold under the name Eupatorium rugosum 'Chocolate', is grown in gardens for its dark-tinted foliage. The darkest color, which is a chocolatey black, occurs in plants grown in a sunny location. The plants are shade-tolerant and do best in moist soils.[9] More recently, the plant can be found under the correct species name.

See also[edit]

References[edit]

  1. ^ "The Plant List: A Working List of All Plant Species". 
  2. ^ a b "USDA GRIN Taxonomy". 
  3. ^ "Ageratina altissima (Linnaeus) R. M. King & H. Robinson var. roanensis (Small) Clewell & Wooten". Flora of North America. 
  4. ^ "Ageratina altissima (Linnaeus) R. M. King & H. Robinson var. altissima". Flora of North America. 
  5. ^ "Nancy Hanks Lincoln", National Park Service
  6. ^ W. D. Snively, Minnesota Medicine, V. 50, April 1967, pp. 469-476
  7. ^ John W. Allen, It Happened in Southern Illinois, Carbondale: Southern Illinois University Press, 1968 (reprint, paperback, 2010 - Googlebook version), pp. 5-6, accessed 1 July 2011
  8. ^ "Medicinal Plants-White Snakeroot". Bio.brandeis.edu. Retrieved 2013-11-05. 
  9. ^ "Eupatorium rugosum 'Chocolate'". Missouri Botanical Garden. 
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