Dear Friends of Maine Lakes, Thank you for visiting our Interactive Field Guide! Though the primary content pertaining to species identification in this Guide isβ€”for the most partβ€”still correct and useful, the site itself is no longer fully-functional (nor able to be updated). The entire Guide will soon be replaced by a new, expanded website-version of the Maine Field Guide to Aquatic Phenomena. So please stay tuned! Thank you for your patience!

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Adventious roots

Adventicious roots – Slender hair-like roots that emerge along the growing stem or stem fragment.* Go Back

Alternate Leaves

Alternate – Leaves spaced singly along a stem, one at each node.* Go Back

Leaf Axil

Axil – The angle created between two structures on a plant, such as the notch formed between the base of a leaf and the stem. Go Back


Beak – A beak-like protrusion, generally used to describe the shape of a seed.* Go Back

Leaf Blade

Blade – The expanded portion of a leaf, in contrast to the leaf stalk.* Go Back


Bracts – Small specialized leaves that are directly associated with a flower or fruit. Go Back


Branch-divided – A divided leaf pattern in which the leaflets branch from the leaf stem many times like the branches of a tree.Go Back

Clone – A form of asexual reproduction such as budding, fragmentation, and tubers that produces a genetically identical plant.Go Back

Divided (Finely divided) – Used to describe a compound leaf that is divided into distinct parts called leaflets; a leaf may be divided in various ways, for example, it may be fork-divided, branch-divided, or feather-divided. Go Back

Double node – Two nodes occurring together; in some species a point from which new branches or flower stalks emerge. Go Back

Emergent – Plants have leaves that extend above the water surface, usually found in shallow water.* Go Back

See Littoral Zone

Feather Diveded Leaves

Feather-divided – A compound leaf with slender pairs of leaflets arranged in two opposite (or roughly opposite) rows along a common midrib; a pinnate leaf with thread-like leaflets. Go Back

Floating-leaf – Describes plants that produce leaves that typically float on the surface.Go Back

See Littoral Zone

Forked Leaves

Fork-divided – Leaf or leaflet that divides by forking one or more times (generally less than three). Go Back

Fruit – The seed bearing portion of a plant. Go Back


Gland – A protrusion or depression on a structure that produces a sticky or greasy substance. Go Back

Lacuna (plural: Lacunae) – A space or gap located within tissues. Go Back

Littoral Zone – The near shore shallow water zone of a lake, where light reaches the bottom and aquatic plants grow. Go Back
Littoral Zone

Leaf Mid-Rib

Mid-rib – The central vein of a leaf that runs from the tip to the base of the leaf. Go Back


Node – The point on a stem from which a leaf or branch grows. Go Back

Nut or Nutlet – Dry fruit having a hard shell which usually contains only one seed. Go Back

Opposite Leaves

Opposite – Leaves are arranged on the stem in pairs, directly across from one another.* Go Back


Petiole – A leaf stalk. Go Back


Pinnate – A compound leaf with three or more pairs of leaflets arranged in two opposite rows along a common stalk. See Feather Divided. Go Back


Rhizome – A creeping underground stem.* Go Back

Floating Rosette

Rosette – An arrangement of leaves in a radiating pattern at the base of the plant.* Go Back

Serrated Leaves

Serrate – A sharply toothed leaf margin. Serrations are conspicuous on some species; on other species they may only be visible with magnification.* Go Back


Sheath – A portion of the leaf that wraps around the stem of the plant. Go Back


Spike – Flowers spaced closely on a single stalk.* Go Back

Stigma – The pollen receiving tip of a flower's pistil* Go Back


Stipule – An appendage at the base of a leaf stalk. Go Back


Stolon – A stem that creeps along the surface of the sediment or ground.* Go Back

Sub-opposite leaf arrangement

Sub-Opposite – Leaves almost opposite each other on the stem, but not precisely opposite.

Submersed – Describes plants that have most of their leaves growing underwater. Submersed plants may also produce floating leaves or emergent flowering stalks. Go Back

See Littoral Zone


Tuber – A bulb-like structure produced along the rhizome. Tubers provide food storage and facilitate asexual reproduction. Go Back


Turion – A compacted vegetative bud produced along the stem that can overwinter and form a new plant. Also known as winter buds. Go Back

Winter bud – See Turion. Go Back

Whorled Leaves

Whorled – An arrangement of three or more leaves, flowers or bracts radiating from a central point on a stem. Go Back

*From “Through the Looking Glass…A Field Guide to Aquatic Plants” By Susan Borman, Robert Korth, & Jo Temte. Available online at:

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