Common knotweed vs Gray-shanked Douc Langur

Polygonum plebeium compared with Pygathrix cinerea

Key Differences

• Common knotweed is Not Evaluated while Gray-shanked Douc Langur is Critically Endangered.

Taxonomic Classification

Rank	Common knotweed	Gray-shanked Douc Langur
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Chordata (Chordates)
Class	Magnoliopsida (Dicots)	Mammalia (Mammals)
Order	Caryophyllales (Caryophyllales)	Primates (Primates)
Family	Polygonaceae	Cercopithecidae (Old World Monkeys)
Genus	Polygonum	Pygathrix
Species	Polygonum plebeium	Pygathrix cinerea

Conservation Status

Common knotweed

NE — Not Evaluated

Gray-shanked Douc Langur

CR — Critically Endangered

Physical Characteristics

Attribute	Common knotweed	Gray-shanked Douc Langur
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic 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).

Gray-shanked Douc Langur

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

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.