Hydrilla verticillata (L.f.) Royle

First published in Ill. Bot. Himal. Mts.: t. 376 (1839)
This species is accepted
The native range of this species is Poland to Asia, Australia to W. Pacific, Uganda to N. Zambia. It is a hydrosubshrub and grows primarily in the wet tropical biome. It is used as animal food and a medicine, has environmental uses and for food.


Elevation range: 250–250 m a.s.l. Naturalised in Colombia. Colombian departments: Cundinamarca.
Herb, Aquatic.
IUCN Red List Assessment (2021): LC.
Habitat according IUCN Habitats Classification: artificial - terrestrial.

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Nativa en Colombia; Alt. 250 - 250 m.; Valle del Magdalena.
Morphology General Habit
Hierba, acuática
No Evaluada

J. R. Timberlake, E. S. Martins (2009). Flora Zambesiaca, Vol 12 (part 2). Royal Botanic Gardens, Kew

Type India, Linnean Herb no.11066- (LINN lectotype).
Morphology General Habit
Annual or perennial submerged aquatic herb
Morphology Roots
Roots long and simple, adventitious, arising at nodes
Morphology Stem
Stems either creeping and stoloniferous or erect, terete, slender, 0.3–0.8 mm wide, up to 2(3) m long, usually reddish, freely branched near base, usually sparingly branched above
Morphology Leaves
Leaves opposite on stolons or at base of stem or branch, ovate or widely ovate, rarely more than 4 mm long, but whorled (3–12) on the erect stem and branch, mostly linear to narrowly lanceolate, sometimes widely ovate, (7)12–20 mm long (rarely more), 1.5–4 mm wide, soft, green, often with reddish-brown spots and stripes, wide and partly embracing stem at base, acute at apex; midrib distinct, sometimes with unicellular spines underneath; margins with 1–3 rows of translucent cells and unicellular spines, regularly spaced, pointing upwards, mostly visible to the naked eye
Morphology General Scales
Intravaginal scales narrowly triangular to lanceolate, c.0.5 mm long, translucent, with finger-like orange-brown hairs
sex Male
Male infloresences on peduncle up to 1 mm long, spathes comprising 2 pear-shaped or globose united bract, c.1.5 mm wide, with 8–16 subulate appendages; male flowers with pedicel c.0.5 mm long, sepals strongly convex at anthesis, 1.5–3 mm × 2 mm, green at base, reddish higher, petals elongate, ± spathulate, whitish or reddish
sex Female
Female spathes solitary or rarely 2 in leaf axils, sessile, cylindrical but tapering outwards, translucent or reddish-brown, disintegrating as fruit ripens; female flowers with filiform hypanthium, 15–100 mm long, sepals 2–4 mm long, translucent, streaked with red or white, petals transparent, occasionally with reddish streaks, staminodes colourless, ovary pink, 2–3 mm long, containing up to 10 ovules, stigma 0.75–1 mm long, whitish to pinkish-purple
Morphology Reproductive morphology Fruits
Fruit cylindrical, 5–10(15) 1.5 mm, smooth or with lateral linear processes, developing under water
Morphology Reproductive morphology Seeds
Seeds 2–5(7), borne in a linear sequence, c.2.5 mm long, brown.
Zambia, Mozambique. Widely distributed in Asia, New Guinea and Australia, probably also native in NE Europe. In Africa probably native in and around the central African lakes (Congo, Rwanda, Burundi, Uganda, Kenya, Tanzania, N Zambia), but a recent introduction elsewhere (Canary Is., Ivory Coast, Mozambique, Réunion and Mauritius); absent from Madagascar.
In lakes, swamps, irrigation ditches and slowly flowing waters up to 3 m deep, sometimes invasive; 90–800 m (to 1950 m in East Africa).
Conservation notes Introduced across most of its range in the Flora area; not threatened.
Hydrilla verticillata shows much variation in robustness, the number of leaf in each whorl, leaf length and shape, the number of rows of marginal cells, degree of ramification of stem, length of internodes, etc. Isoenzyme analysis and random amplified DNA analysis show the existence of several population groups of Hydrilla according to geographical origin. The plants from the East African Great Lakes have short, leathery, ovate and mostly recurved leaf, and are always sterile. They can be confused with Lagarosiphon ilicifolius, especially when both species grow together. They can be distinguished by examining the lower leaf on stem and branch – in Hydrilla leaf are in whorls while in L. ilicifolius they are spirally arranged. Moreover, the leaf apex bears only 1 spine in Hydrilla and 2 in Lagarosiphon

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/167871/65905991

LC - least concern

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Predicted extinction risk: not threatened. Confidence: confident


Use Animal Food
Used as animal food.
Use Environmental
Environmental uses.
Use Food
Used for food.
Use Medicines
Medical uses.


  • Angiosperm Extinction Risk Predictions v1

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