Transcript Bushy pondweed - Thomas Tisue, Ph. D.

A Gallery of White Lake’s
Aquatic Macrophyte
Community
Bulrush



Found mostly along shallow margins in water < 3 ft deep
Represented by several species, including Scirpus pungens (l.) and Scirpus
americanus (r.), the latter readily distinguishable by triangular stem
Highly desirable as habitat and for erosion control, but unacceptable in
swimming areas; seeds are important waterfowl food
Bushy pondweed



Leaves opposite but
with bundles of other
leaves at the base of
each leaf, giving the
appearance of being
whorled; leaves 0.5 1.5 inches in length
Generally beneficial
More than one
species from the
Najas family, but all
similar in
appearance
Cattails
Separate male and
female parts




Left: common cattail (Typha latifolia); right: narrow leaf cattail (Typha augustifolia);
frequently hybridize, forming Typha xglauca
Narrow leaf cattail and hybrids displace common cattail and are often invasive
Male and female parts of flower are separated on the stems of narrow leaf cattail
Beneficial as habitat, for erosion control, as a natural visual screen and as muskrat
food source; not desirable in swimming areas; can spread rapidly when water levels
change; tolerant of variation in soil moisture (seasonal standing water)
Muskgrass/Stonewort




Brittle, rough texture; short leaves; produces musky odor when
crushed
Chara family of macro algae; not rooted
Highly desirable, except when thick mats develop in swimming
areas
Similar in appearance to undesirable starry stonewort
Clasping leaf pondweed





2 - 3 inch leaves wrap around stem, hence the name
Systematic name: Potamogeton richardsonii
Generally desirable, but can form dense beds
Easily confused with the undesirable Curly leaf pondweed, which has leaves with
finely toothed edges not present on clasping leaf
Shares many attributes with White stem pondweed
Coontail




Leaves have coarse serrations and
form whorls around stem that grow
more closely packed towards upper
stem ends
Has desirable characteristics as
habitat but can form very dense
beds to the detriment of other
species
Not rooted, although lower parts
may be covered by surface
sediments, and thus spreads
through mechanical disruption
Systematic name: Ceratophyllum
demersum
Eurasian water milfoil
Generally undesirable as habitat; tendency
to form heavy beds that emerge from surface and
interfere with navigation and other recreational
uses; fragile and easily spread by mechanical
disruption
Not always readily distinguishable from native
milfoil, with which it also forms hybrids with
mixed characteristics
Systematic name: Myriophyllum spicatum
Eel grass/Wild
celery




Long, ribbon-like leaves emerging from a rooted base; reproductive
parts borne on helical threads extending to surface
Highly desirable as habitat and food for water fowl
Systematic name: Vallisneria americana
Resistant to herbicides and spreads when they are used to control
other plants
Fern-leaf pondweed



Leaves extending in nearly opposite directions in a single plane
so that the entire plant appears somewhat flat, especially when
seen in water
Generally beneficial; good fish habitat
Systematic name: Potamogeton robbinsii
Illinois
pondweed



Prominent stipule


Leaves 2 - 6
inches with sharp
tips
Almost always
beneficial; good
habitat and
waterfowl forage
Tends to grow in
diverse
communities with
other species
Systematic name:
Potamogeton
illinoensis
Very similar to
American
pondweed
(Potamogeton
nodosus)
Native milfoil



But…there is often sufficient overlap in leaflet
counts to make clear distinctions difficult
Similar in appearance and
growth characteristics to
invasive Eurasian water
milfoil (EWM)
Native milfoils are more
subject to predation by
indigenous milfoil weevils
than EWM and tend to be
less of a nuisance as a
result
Hybrids with EWM exhibit
mixed characteristics;
genotyping required!
Sago
pondweed




Leaves 2 or more inches with sharp tips; tends to tall, bushy growth, often extending to the
water surface, where it can create a nuisance
Excellent habitat for small invertebrates and as fish forage
Subject to biological controls over time but tends to spread when other species are
controlled with herbicides
Systematic name: Stukenia pectinata (formerly Potamogeton pectinatus)
Thin leaf
pondweeds



Consists of many Potamogeton species with 2 - 3 inch thready leaves,
appearing somewhat sparse and fragile
Generally grows together in mixed beds with other species, providing
desirable fish habitat; valuable as food source for waterfowl
Seldom grows to surface; largely beneficial with no significant negative
characteristics
Variable pondweed



Submerged leaves vary in size and shape, hence the name; sometimes
puts out floating leaves that are larger and wider
Desirable species growing in mixed beds with Potamogeton species,
and others
Systematic name: Potamogeton gramineus
Waterweed/Elodea




Never more than 3 leaves in a whorl
Beneficial as habitat and food source
Low recreational impact
Systematic name: Elodea canadensis
Closely resembles the invasive and
highly undesirable Hydrilla, which usually
has up to 5 leaves in each whorl
White water lily






Distinctive, lotus-like flowers with pleasing fragrance
Several Nymphaea species of similar appearance
Note absence of distinct mid-rib in leaves, which emerge at the surface on a single stem
Grows from a large root buried in the lake bottom
Usually found in water < 5 ft deep, where organic matter is abundant in sediments
Highly desirable, except as an impediment to recreation when present in large beds
White stem pondweed




Similar to clasping leaf pondweed in most respects; tall, leafy growth pattern
Can form dense beds that reach the water surface, sometimes interfering with
recreational uses
Characterized by 4 - 8 inch submersed leaves as well as stem color
Systematic name: Potamogeton praelongus
Yellow water lily




Represented by several similar Nuphar species (Nuphar lutea shown)
Characteristics similar to white water lily except flower color
Floating leaves have pronounced mid-rib
Desirable except when present in dense beds that interfere with navigation
Notes





Color photographs are from public-domain Internet sources
Line drawings and some descriptive material were adapted from Howard D.Wandell and
Lois G.Wolfson, A Citizen's Guide for the Identification, Mapping and Management of the
Common Rooted Aquatic Plants of Michigan Lakes (2nd ed.), Michigan State University
Extension, May 2007. This publication is accessible online at:
www.micorps.net/documents/CommonRootedAqPlants-MSUE-WQ-55.pdf
This gallery is intended for general use. Please consult Wandell and Wolfson for more
complete and definitive information.
A second WLA Gallery of photos focuses on potential invasive species not yet reported to
occur in White Lake
We gratefully acknowledge the assistance of more than two dozen volunteers from the
riparian community, the White Lake Association (which also provided financial assistance),
and the White River Watershed Partnership, as well as technical back-stopping by the Anis
Water Resources Institute and the Muskegon Conservation District
Thomas Tisue, Thomas Hamilton
February, 2014