Common Kidney-Vetch vs Common Knotweed

Anthyllis vulneraria compared with Polygonum arenastrum

Key Differences

• Common Kidney-Vetch is Vulnerable while Common Knotweed is Not Evaluated.

Taxonomic Classification

Rank	Common Kidney-Vetch	Common Knotweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order	Fabales (Legumes & Allies)	Caryophyllales (Caryophyllales)
Family	Fabaceae	Polygonaceae
Genus	Anthyllis	Polygonum
Species	Anthyllis vulneraria	Polygonum arenastrum

Evolutionary Relationship

Common Kidney-Vetch and Common Knotweed share a common ancestor at the Class level: Magnoliopsida. (Dicots)

Conservation Status

Common Kidney-Vetch

VU — Vulnerable

Common Knotweed

NE — Not Evaluated

Physical Characteristics

Attribute	Common Kidney-Vetch	Common Knotweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Kidney-Vetch

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, temperate broadleaf and mixed forests, and temperate coniferous forests, among 6 distinct biome types spanning the Indomalayan and Oceanian and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Libya), Asia (Japan), Europe (9 countries), North America (Canada, United States), and Oceania and the Pacific (Australia). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Knotweed

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Widely distributed across Asia (Taiwan), Europe (10 countries), and North America (Mexico, United States).

Common Kidney-Vetch

Common Kidney-Vetch (<em>Anthyllis vulneraria</em>) is a flowering plant in the legume family Fabaceae, assessed as Vulnerable on the IUCN Red List due to habitat degradation and agricultural intensification across parts of its range. It is widely distributed across Africa (Libya), Asia (Japan), Europe (nine countries), North America (Canada and the United States), and Oceania (Australia), occupying six distinct biome types and occurring within the Indomalayan and Oceanian biogeographic realms. The species typically grows in dry, calcareous grasslands, coastal cliffs, sand dunes, and rocky slopes, often favoring nutrient-poor soils. It is an important larval food plant for certain butterfly species, particularly the Small Blue butterfly in Europe, and contributes to soil fertility through nitrogen fixation via root nodules. Its cheerful yellow, orange, or red flower heads make it a recognizable component of chalk and limestone grassland communities. Biological traits of this species remain poorly documented in the scientific literature.

Common Knotweed

Common Knotweed (<em>Polygonum arenastrum</em>) is a prostrate annual herb in the family Polygonaceae, distributed across Asia, Europe, and North America. Its native range encompasses Taiwan in Asia, ten European countries, and Mexico and the United States in North America. The species typically colonizes highly disturbed, compacted substrates such as footpaths, roadsides, cultivated ground, and waste places, exhibiting a strong association with anthropogenic disturbance. Its wiry, branching stems and small, pale pink flowers form dense mats close to the ground, making it well adapted to trampled environments. The conservation status of this species has not been formally evaluated by the IUCN. As a cosmopolitan ruderal plant, it is broadly tolerant of environmental stress and contributes to ground cover in highly modified habitats throughout the temperate zone. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 6 countries:

🇧🇪 Belgium 🇫🇷 France 🇳🇱 Netherlands 🇳🇴 Norway 🇬🇧 United Kingdom 🇺🇸 United States