BugwoodWiki Article

oxygen weed
Lagarosiphon major (Ridley) Moss


Lagarosiphon major is a perennial, submerged aquatic plant that can grow in dense mats up to 6.6-9.8 ft. (2-3 m) thick.
The stems, which can reach the surface, are brittle and sparsely branched, 0.12-0.2 in. (3-5 mm) in diameter and curved towards the base (J-shaped). The leaves are 0.2-0.8 in. (5-20 mm) long and 0.08-0.12 in. (2-3 mm) wide, and occur in alternate spirals along the stem.
The flowers have three petals and are very small 0.01 in. (0.25 mm) in diameter and up to 2.4 in. (6 cm) long, and clear-white to pink on the surface.
The fruit capsule is beaked with seeds 0.13 in. (0.32 cm) long, averaging nine to a fruit. Lagarosiphon major can also reproduce by stem fragments.
Ecological Threat
Lagarosiphon major is fast-growing and may completely fill the volume of a large shallow lake up to 9.8 in. (3 m) deep. It is native to southern Africa.

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State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org

State Invasives List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Alismatidae
Order: Hydrocharitales
Family: Hydrocharitaceae
Genus: Lagarosiphon

Other System Links

Plants: LAMA15
GRIN: 316415
ITIS: 565981

Synonyms and Other Names

Other Common Names:
oxygen-weed, African elodea,South African oxygen weed


Category: Aquatic