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Federal Noxious Weed
TDA Noxious Weed
TPWD Prohibited Exotic Species
Invasive Plant Atlas of the US

NOTE: means species is on that list.

Lagarosiphon major


Oxygen-weed

Synonym(s):
Family: Hydrocharitaceae (Tape-Grass Family)
Duration and Habit: Perennial Herb


Photographer: Rohan Wells
Source: National Institute of Water & Atmospheric Research, Bugwood.org

Description

A rhizomatous, perennial, submerged aquatic plant. It has numerous threadlike roots, which are 'adventitious' (branching from the stem) and, along with rhizomes (horizontal stems in the sediment), anchor it to the bottom. Stems, which can reach the surface, are brittle and sparsely branched, 3-5mm in diameter and curved towards the base (J-shaped). The leaves are 5-20mm long and 2-3mm wide, and occur in alternate spirals along the stem. They generally have tapered tips curving downwards towards the stem, except in low alkalinity water where they are straight. The three-petalled female flowers are very small, clear-white on the surface, and grow on very thin white to almost translucent filament-like stalks.

Ecological Threat: Lagarosiphon major is fast-growing, may totally fill the volume of a large shallow lake (to 3 m deep, fills water control channels, in New Zealand, Lagarosiphon major is a major aquatic weed problem recorded in many lakes,

Biology & Spread:

History:

U.S. Habitat: lakes, riparian zones, water courses, wetlands

Distribution

U.S. Nativity: Cultivated, or not in the U.S.

Native Origin: Native in southern Africa

U.S. Present: Happily, Lagarosiphon major does not yet occur in the wild in the United States, as 2008, so far as is known. However, experts have reason to believe that should this plant be introduced to the U.S., the resulting problems could be as consequential as those caused by another plant in the Hydrocharitaceae family, hydrilla (Hydrilla verticillata)

Distribution: Under favourable conditions, dense growth of the plant can block light penetration into waterways, eliminating growth of native water plants and affecting associated populations of aquatic invertebrates and vertebrates. Once widespread, control would be extremely difficult (as is the case for most submerged aquatics)

Mapping

Invaders of Texas Map: Lagarosiphon major
EDDMapS: Lagarosiphon major
USDA Plants Texas County Map: Lagarosiphon major

Resembles/Alternatives

Management

USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.

Text References

Center for Aquatic Invasive Plants. 2009. African elodea. University of Florida. Accessed 19 August 2010 (http://plants.ifas.ufl.edu/node/220).

Online Resources

Search Online

Google Search: Lagarosiphon major
Google Images: Lagarosiphon major
NatureServe Explorer: Lagarosiphon major
USDA Plants: Lagarosiphon major
Invasive Plant Atlas of the United States: Lagarosiphon major
Bugwood Network Images: Lagarosiphon major

Last Updated: 2009-02-03 by HTG
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