Leaf Arrangement for Identification
Vegetation Identification
As previously stated, Vegetation Identification is a very critical first
step in managing your pond. With the vast numbers of plant species that
you could potentially encounter it's often difficult for the average
pond owner to narrow down their choices. Most aquatic plants can be
broken down into four major groups, Algae, Submerged, Emergent and
Floating.
Vegetation Identification
Algae - This group of "plants" is often the most problematic, but these
can often be easily controlled.
Submerged Plants - These are the plants that grow, typically rooted from
the bottom, and grow near the water’s surface. Some species will even
have portions of the plant slightly above the water line. Of all the
plant groups these are the most difficult to control. Hydrilla is the
most well know submerged plant.
Emergent Plants - Shoreline vegetation and any other rooted plant that
grows above the water line is considered Emergent. Cattails are a
perfect example.
Floating Plants - Floating vegetation is just that, free floating on the
surface of the water; often with exposed roots just below the waterline.
Some of the most invasive plants are floating plants such as, Giant
Salvinia, Hyacinth etc.
Navtive and Non-Native Plants
The following was taken from the United States Environmental
Protection Agency.
What is a Native Pant?
Native plants (also called indigenous plants) are plants that have
evolved over thousands of years in a particular region. They have
adapted to the geography, hydrology, and climate of that region. Native
plants occur in communities, that is, they have evolved together with
other plants. As a result, a community of native plants provides habitat
for a variety of native wildlife species such as songbirds and
butterflies.
What is a Non-Native Plant?
Non-native plants (also called non-indigenous plants, invasive plants,
exotic species, or weeds) are plants that have been introduced into an
environment in which they did not evolve. Introduction of non-native
plants into our landscape has been both accidental and deliberate.
Purple loosestrife, for example, was introduced from Europe in the
1800's in ship ballast and as a medicinal herb and ornamental plant. It
quickly spread and can now be found in 42 states.
In general, aggressive, non-native plants have no enemies or controls to
limit their spread. As they move in, complex native plant communities,
with hundreds of different plant species supporting wildlife, will be
converted to a monoculture. This means the community of plants and
animals is simplified, with most plant species disappearing, leaving
only the non-native plant population intact.
For example, purple loosestrife colonizes wetland areas, replacing
native plants unable to compete for available sunlight, water, and
nutrients. Wetlands infested with purple loosestrife lose as much as 50%
of their original native plant populations. This limits the variety of
food and cover available to birds and may cause the birds to move or
disappear from a region altogether.
Opposite leaf patterns are somewhat easier to identify. They are
straight forward, having two leaves directly across from one
another,
each on opposite sides of the stem. In an opposite pattern you could
draw a line from leaf 1 to leaf 2 and it would be perpendicular to the
stem. See drawing at left.
An Alternate pattern is when the first leaf is on the left side and the
second leaf is located up the stem and on the right side of the stem;
this pattern then "alternates" left, right, left right and so on.
However the very tips of the plant may be too closely grouped to
distinguish a pattern so be sure to take multiple sample from the same
plant before declaring the pattern.
One critical aspect of plant identification that is too often overlooked
is Leaf Arrangement. The manner in which the leaves of a plant are
arranged on the stem can often be the determining factor in properly
identifying it. There are three basic styles that we will concentrate on
for now; Alternate, Opposite, and Whorled.
Plants that exhibit a whorled pattern have three or more leaves attached
to the stem at the same level and basically circle the stem. This can
often give the vegetation a tubular appearance
Not all Plants that we encounter in and around our ponds will fit into
these categories. Cattails for example can't clearly be defined as one
of our three choices but the bulk of plants will. Something as simple as
leaf arrangement can help you clear the last hurdle of identifying your
vegetation and should be something that you condition yourself to look
at. For example, early in the growing season Bushy Pondweed and Sago
Pondweed closely resemble one another; at these times knowing that
Bushypondweed is always opposite and Sago ponweed is alternate can be
the difference. When you consider that the products used on Sago
Pondweed may not be effective on Bushy Pondweed you begin to see the
importance of proper Identification.