Common Water Clover vs Polar bear

Marsilea quadrifolia compared with Ursus maritimus

Key Differences

Common Water Clover is Not Evaluated while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Water Clover	Polar bear
Kingdom	Plantae (植物)	Animalia (動物)
Phylum	Tracheophyta	Chordata (脊索動物)
Class	Polypodiopsida (ウラボシ綱)	Mammalia (哺乳類)
Order	Salviniales (水生シダ類)	Carnivora (ネコ目)
Family	Marsileaceae	Ursidae (Bears)
Genus	Marsilea	Ursus (Bears)
Species	Marsilea quadrifolia	Ursus maritimus

Conservation Status

Common Water Clover

NE — Not Evaluated

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	Common Water Clover	Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Common Water Clover

Habitat

Typically found in moist, shaded forest floors and tropical canopies.

Range

Widely distributed across Asia (India, Vietnam), Europe (5 countries), and North America (Canada, United States).

Polar bear

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Water Clover

<em>Marsilea quadrifolia</em>, commonly known as the common water clover or European waterclover, is an aquatic fern in the family Marsileaceae. Its conservation status is listed as Not Evaluated by the IUCN. The species has a broad native distribution spanning Asia and Europe, and has been introduced to North America, where it now occurs in scattered freshwater habitats. It typically grows in shallow ponds, rice paddies, slow-moving streams, and muddy lake margins, rooting in soft sediments while its four-leaflet fronds float on or emerge above the water surface. The distinctive four-lobed leaves strongly resemble a four-leaf clover, lending the plant its common name. <em>Marsilea quadrifolia</em> is a heterosporous fern, producing specialized reproductive structures called sporocarps that contain both megaspores and microspores, allowing reproduction under conditions unfavorable for vegetative growth. The plant is remarkably drought-tolerant, as sporocarps can remain viable for decades. It typically spreads through both vegetative rhizome growth and spore dispersal. Biological traits including average lifespan, height, and mass remain poorly documented in standardized databases. The species plays a role in shallow aquatic ecosystems as a colonizing plant, stabilizing soft substrates and providing microhabitat for invertebrates and small vertebrates in the temperate freshwater zones it inhabits.

Polar bear

地球上で最大の陸上肉食動物であるホッキョクグマは700kgを超えることがあり、カナダからロシアまでの北極海氷域全体に分布する。ワモンアザラシとヒゲアザラシを狩るために海氷に依存する高度に特化した海洋哺乳類である。広大な距離を泳ぐことができる優れた泳者でもある。脆弱種に指定されており、気候変動による急激な北極海氷の消失で個体群が深刻な圧力を受けている。