Common invasive Species
Eurasian Watermilfoil
Scientific Name: Myriophyllum spicatum
Submergent
Similar to: Northern watermilfoil
ID:
Stem: thin, flexible, often pinkish red
Leaves: delicate whorled usually spaced 2-3cm apart with 12-20 leaflets per leaf
The tip of the plant is often red in the summer months
No winter buds are produced
Habitat: lakes and streams; shallow to deep areas
Photo credit: USGS
Curly-leaf Pondweed
Scientific Name: Potamogeton crispus
Submergent
Similar to Clasping leaf pondweed
ID:
Stem: Partially flattened
Leaves: Wavy when mature (bacon like) and have serrated edges
Have a predominate midvein and a blunt tip
Does not produce floating leaves
Fruits are 5-5.5mm with 3 ridges
Habitat: Highly variable; Lakes and streams; shallow to deep
Photo credit: Aquatic Biologists
European Frogbit
Scientific Name Hydrocharis morsus-ranae
Free floating plant
ID:
Floating heart shaped leaves with long stems
White cup shaped flower with yellow center
Roots are normally 8-12 inches long
Can form floating dense mats
Habitat: Shallow slow-moving lakes or streams
New Invasive in Wisconsin, found in 2021
Around shores of Lake Michigan
Zebra Mussel
Scientific Name: Dreissena polymorpha
Similar to: Quagga Mussel (Invasive)
ID:
D shaped, Have a flat bottom
Light to dark stripes running along shell
Size: pea to quarter
Can attached to several items including fishing line and other Zebra Mussels
Chinese Mystery Snail
Scientific Name: Cipangopaludina chinensis
Similar to: Banded Mystery Snail
ID:
Can grow up to 2 in long
Light to dark brown color
Has 7-8 whorls on shell
Have an operculum “trapdoor” at opening of shell
Habitat: Found in lakes and slow-moving rivers
Photo Credit: University of Minnesota Extension
Banded Mystery Snail
Scientific Name: Viviparus georgianus
Similar to: Chinese Mystery Snail
ID:
Can grow up to 1 ¾ in long
Color is yellow to green with brown to red bands
Has 4-5 whorls on Shell
Habitat: Found in lakes and slow-moving rivers
Photo Credit: inaturalist
Rusty Crayfish
Scientific Name: Orconectes rusticus
ID:
Tips of claws with black bands
Sides of Crayfish with dark red (rust) spots
When claw is closed it has an oval gap
Claws are grey greenish to reddish brown in color
Generally, 3-5 inches long
Photo Credit: Wisconsin Department of Natural resources
Spiney Water Flea
Scientific Name: Bythotrephes longimanus
ID:
Bulbus egg pouch
Prodominent, tiney dark eye spot
Straight tail
1-4 pairs of barbs on tail
Clumps together to look like gelatin
Hard to see without magnification
Prefer deep lakes
Abundant June-September depending on water temperature
Photo Credit: Sate of Michigan
Starry Stonewort
Starry Stonewort
Scientific Name: Nitellopsis obtuse
ID
Bright green branches
Root like filaments with starshaped bulbis
Length of leaf like branches can vary between plants
Photo Credit: Paul Skawinski
Purple loosestrife look-a-likes
Look-A-Likes
Both of these plants in the photo on the left are commonly seen along highways and right of ways in Northern Wisconsin. Both of these plants from the roadway look very similar. At a closer look, you an see the differences between the two. One species is native and the other is invasive
The Native Species- Fireweed
(Left in photo) ID: Fat (2-4”) spikes of 4-petaled stalked flowers, alternate toothed leaved, northern plant of drier areas.
The Invasive Species- Purple Loosestrife
(Right in photo) Flowers in a spike formation, closely attached to stem, 5-6 petals per flower, opposite leaf arrangement,