Gen info
- Ageratina, commonly known as snakeroot, is a genus of over 300 species of perennials and rounded shrubs in the family Asteraceae.
- Ageratina riparia, commonly known as mistflower, is a species of flowering plant in the family Asteraceae, native to Mexico. Widely adventive, it has spread to Cuba, Jamaica, and other parts of the Caribbean. It has been introduced as an ornamental plant and has become naturalized in various regions of the world, including Hawaii, South Africa, Southeast Asia, Macronesia, Oceania, Peru, and the Indian subcontinent. (3)
- Taxonomy: Species was identified by Eduard Regel as Eupatorium riparium in the 1866 edition of Gartenflora. It was reclassified as a member of the genus Ageratina by Robert Merrill King and Harold E. Robinson in the 1970 edition of Phytologia. (3)
- Etymology: The genus name Ageratina derives from Greek meaning "un-aging", referring to the plant flowers retaining its color for an extended period of time. The specific epithet riparia derives from Latin word ripa meaning "riverbank" or "streambank", and the suffix -aris denoting it "belongs to" the bank, together meaning "growing on the banks". The Hawaiian pamakani means "windblown", referring to the wind dispersal of the seeds. (3)
- Mature plants can produce around 10,000 to 100,000 seeds per year, which are dispersed by wind and flowing water. (3)
- There is evidence that the plant's decaying matter produces allelopathic compounds, which may inhibit the germination of native flora. It adversely affects grazing pastures, and can be toxic to horses, and is often avoided by grazing stock. (3)

Botany
• Mistflower is a low growing, sprawling perennial herb that may grow up to 1 meter in height in some climates. The species has a fibrous rootstock and its stems are often woody and covered in purple hairs. The stems may produce additional roots if they contact the ground.

• Stems: Hairy and becomes glabrous near the end, produces creeping stems that root at the nodes, forming a dense mat of interwoven stems, purplish. Leaves: Simple, opposite, petiole 1 to 13 mm long, margins sharply serrate, elliptical to lanceolate, with acuminate end, measures 3,5-10 cm long and 1 to 1,5 cm wide. Flowers: Numerous small white flower-heads clustered together at the tips of the branches, contains around twenty tubular flowers, 3 to 3,5 mm long, arranged in loose corymbs. The lateral branches are underpinned by 2 leafy bracts. The capitulum grouped in small corymbs. The flower's heads are bell-shaped, measure 2 mm in diameter. Fruits: Prismatic achene with 5 ribs, of 1,5 to 2 mm long, dark brown to black, hairy.

Distribution
- Introduced, naturalized. (1)
- In Luzon: Benguet, Mountain Province, Nueva Viscaya.
- Native to Mexico. (2)
- Introduced in the U.S. as an ornamental plant and by agricultural contamination.
- Highly invasive in tropical and warm temperate climates, where the species can form dense underbrush. (3)

Constituents
- Methylripariochromene A (1), ripariochromene A (2), ripariochrome B (3), ripariochromine C (4) and eupatoriochromene (5) have been isolated from Australian species of A. riparia.  Jamaican species have yielded acetovanillochromene (6). Taraxasterol, taraxasteryl acetate, taraxasteryl palmitate, epi-friedelinol and sigmasterol have been reported from Indian A. riparia. (see study below) (6)

Properties
- Study suggested antifungal properties.

Parts used
Leaves.

Uses
Edibility
- Leaves and flowers used for making herbal tea.
Folkloric
- In the Philippines,  crushed leaves used for tumorous inflammation, boils, and "kulebra".
- In India, herbal tea made from dried leaves and flowers used to reduce blood pressure and blood sugar. (3)
- In Indonesia, us for treating wounds and to stop bleeding.
- In Nigeria, used for wound healing, treatment of hemorrhoids, and as anthelmintic.
- In Vietnam, leaves used for treatment of skin infections, burns, and soft tissue wounds.
Others
- Agroforestry: Used for stabilization of embankments and for partitioning land. (3)
- Veterinary: Crofton weed toxicity could not be excluded as potential cause of equine interstitial pneumonia or pulmonary fibrosis in Australia.

Studies
• Antifungal Against Banana Anthracnose Disease / Aerial Parts: Study evaluated the antifungal components of the weed A. riparia and their ability to control banana anthracnose disease caused by the fungus, Colletotrichum musae. Methylripariochromene A was isolated as a bioactive compound from a methanol extract of aerial part of A. riparia. The ME showed promising reduction of anthracnose lesions at high concentrations. Brine shrimp micro-well cytotoxicity assay showed the commercial fungicide Bavistin FL showed might higher cytotoxicity (100% at 250 ppm) compared to the ME and methylripariochromene A. Results suggest potential of aerial part as natural alternative to commerciall available fungicides for control of banana anthracnose disease. Methylripariochromene A isolated from Sri Lankan  A. riparia showed antifungal activity against Cladosporium cladosporioides, Aspergillus sp., Fusarium sp., Collectrichumgloeosporioides and Cercospora nicotianae (Bandara et al., 1991). (see constituents above) (6)
• Herbicides / Biological Control Agents: Herbicides currently employed against A. riparia include dicamba, glyphosate, metsulfuron, aminopyralid, metsulfuron-methyl, triclopyr, fluroxypyr, picloram, and aminopyralid. Biological agents identified for use in regions where the species is invasive include: the gall fly Procecidochares alani, the plume moth Hellinsia beneficus, and the smut fungus Entyloma ageratinae, species which damage existing plants or inhibit its ability to propagate. (3)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Ageratina riparia / Co's Digital Flora of the Philippines
(2)
Ageratina riparia (Regel) R.M.Kiing & H.Rob. / KEW: Plants of the World Online
(3)
Ageratina riparia / Wikipedia
(4)
jack in the Bush: Ageratina riparia / SOCFINDO Conservation
(5)
Fibrotic Interstitial Pneumonia in 2 Thoroughbred Broodmares / CM Russell, JE Axon, AR Adkins, AP Begg / Australian Equine Veterinarian, 2008; 27(1)
(6)
Potential of the antifungal activity of Ageratina riparia (Regel) R. M. King and H. Rob. against banana anthracnose disease caused by the fungus, Colletotrichum musae / RMND Ratnayake, Ratnayake Bandara, Nimal Adikaram et al / Ceylon Journal of Science, 2018; 47(3) / DOI: 10.4038/cjs/v47i3.7536

DOI: It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page. (Citing and Using a (DOI) Digital Object Identifier)