oxygen weed
Lagarosiphon major (Ridley) Moss

Overview

Appearance

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.

Foliage

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.

Flowers

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.

Fruit

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.

Resources

• Federal Noxious Weed Disseminules of the U.S. - USDA-APHIS

Selected Images

Maps

Invasive Listing Sources

• California Noxious Weeds
• Federal Noxious Weeds
• Indiana Invasive Species Council - Invasive Plant List
• Indiana Pest Species
• Indiana Prohibited Plant Species
• Massachusetts Noxious Weeds
• Massachusetts Prohibited Plant List
• Michigan’s Prohibited and Restricted Species
• Minnesota DNR invasive species list
• New Hampshire Prohibited Aquatic Species
• South Carolina Illegal Aquatic Plants
• Texas Noxious Weeds
• USDA APHIS Regulated Pest List
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References