Common corncockle vs Common knotweed

Agrostemma githago compared with Polygonum plebeium

Key Differences

Common corncockle is Critically Endangered while Common knotweed is Not Evaluated.

Taxonomic Classification

Rank	Common corncockle	Common knotweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order same	Caryophyllales (Caryophyllales)	Caryophyllales (Caryophyllales)
Family	Caryophyllaceae	Polygonaceae
Genus	Agrostemma	Polygonum
Species	Agrostemma githago	Polygonum plebeium

Evolutionary Relationship

Common corncockle and Common knotweed share a common ancestor at the Order level: Caryophyllales. (Caryophyllales)

View Order: Caryophyllales

Conservation Status

Common corncockle

CR — Critically Endangered

Common knotweed

NE — Not Evaluated

Physical Characteristics

Attribute	Common corncockle	Common knotweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common corncockle

Habitat

Found across multiple habitat types including montane grasslands and shrublands, tropical and subtropical moist broadleaf forests, and temperate coniferous forests, among 13 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Lesotho), Asia (7 countries), Europe (24 countries), North America (Canada, Mexico, United States), Oceania and the Pacific (Australia), and South America (Brazil, Chile). Currently classified as Critically Endangered 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 Africa (Madagascar), Asia (Japan, Taiwan), Europe (5 countries), and North America (United States).

Common corncockle

<em>Agrostemma githago</em>, commonly known as common corncockle, is an annual flowering plant in the family Caryophyllaceae. Once a widespread weed of cereal crops across Europe, Asia, and beyond, this species is now Critically Endangered on the IUCN Red List due to the dramatic decline caused by modern agricultural practices, particularly improved grain cleaning and herbicide use. Corncockle is a tall, slender plant covered in silky white hairs, bearing large, solitary pink to purple flowers with distinctive dark veining. Its seeds contain toxic saponin compounds called githagins, which historically contaminated grain supplies. The species now survives primarily in wildflower conservation areas, seed banks, and traditional farmland conservation schemes. It typically grows in open, disturbed arable soils with full sun exposure. Biological traits of this species remain poorly documented in the scientific literature.

Common knotweed

Common Knotweed (<em>Polygonum plebeium</em>) is a low-growing annual herb in the family Polygonaceae, widely distributed across Africa, Asia, Europe, and North America. Its native range includes Madagascar in Africa, Japan and Taiwan in Asia, five European countries, and the United States in North America. The species typically inhabits diverse terrestrial environments including roadsides, cultivated fields, waste ground, and disturbed habitats, often thriving in compacted or trampled soils. It is a small, mat-forming plant with tiny pink or white flowers and narrow leaves, well adapted to anthropogenic landscapes. Its conservation status has not been formally evaluated by the IUCN. The broad distributional range and generalist habitat preferences of this species suggest resilience to moderate levels of disturbance, though its ecological role in native plant communities is less well characterized compared to its weedy occurrences in disturbed sites. Biological traits of this species remain poorly documented in the scientific literature.