Common Water-Nymph vs Spiny naiad

Najas guadalupensis compared with Najas marina

Key Differences

• Common Water-Nymph is Not Evaluated while Spiny naiad is Endangered.

Taxonomic Classification

Rank	Common Water-Nymph	Spiny naiad
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Liliopsida (Monocots)	Liliopsida (Monocots)
Order same	Alismatales (Alismatales)	Alismatales (Alismatales)
Family same	Hydrocharitaceae	Hydrocharitaceae
Genus same	Najas	Najas
Species	Najas guadalupensis	Najas marina

Evolutionary Relationship

Common Water-Nymph and Spiny naiad share a common ancestor at the Genus level: Najas.

Conservation Status

Common Water-Nymph

NE — Not Evaluated

Spiny naiad

EN — Endangered

Physical Characteristics

Attribute	Common Water-Nymph	Spiny naiad
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Water-Nymph

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Widely distributed across Asia (Israel, Taiwan), Europe (4 countries), North America (4 countries), and South America (Brazil, Colombia).

Spiny naiad

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and deserts and xeric shrublands, among 5 distinct biome types spanning the Indomalayan and Neotropic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Sri Lanka, Taiwan), Europe (5 countries), North America (6 countries), and South America (Brazil). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Water-Nymph

<em>Najas guadalupensis</em>, commonly known as the common water nymph or southern naiad, is a submerged aquatic plant in the family Hydrocharitaceae. Its conservation status is listed as Not Evaluated by the IUCN. The species has an extensive distribution spanning Asia, Europe, and the Americas, where it inhabits a wide range of lentic and lotic freshwater environments including ponds, lakes, slow streams, and irrigation channels. It typically grows fully submerged, rooting in sandy or muddy substrates in water ranging from shallow margins to depths exceeding two meters. The plant is slender and branching, with narrow, finely toothed leaves arranged oppositely or in whorls along the stem. <em>Najas guadalupensis</em> is adapted to a range of water quality conditions and can persist in turbid, nutrient-enriched environments where other aquatic macrophytes cannot. It typically reproduces through both seed and fragmentation, with stem fragments readily establishing new colonies. Pollination occurs underwater, with pollen dispersed directly through the water column. Biological traits including average lifespan, stem length, and mass remain poorly documented in standardized databases. Ecologically, common water nymph provides important submerged habitat structure for fish, invertebrates, and waterfowl, offering spawning substrate, foraging areas, and refuge from predators in the diverse freshwater systems it occupies throughout its broad geographic range.

Shared Countries

Both species can be found in 8 countries:

🇧🇷 Brazil 🇨🇺 Cuba 🇩🇰 Denmark 🇸🇻 El Salvador 🇳🇴 Norway 🇸🇪 Sweden 🇹🇼 Taiwan 🇺🇸 United States