Aquatic Invasive Plant Identification
June 26th, 2014 Corey Laxson Aquatic Biologist, Adirondack Watershed Institute Instructor, School of Natural Resource Management and Ecology Paul Smith’s College Visit us at www.adkwatershed.com
Objectives • Develop an understanding of the key anatomical features used to identify aquatic plants. • Strengthen your ability to recognize some of the regionally important invasive plants using the key anatomical features.
Primary Keys for Aquatic Plant ID 1. 2. 3. 4. 5. 6. 7.
Where the plant is growing. Presence or absence of a petiole Leaf arrangement Leaf architecture Characteristics of the leaf edge Shape of the leaf Vienation of the leaf
Primary Keys for Aquatic Plant ID 1. Where the plant is growing. • Emergent plants – plants that grow up and out of the water for the majority of the growing season.
Examples
Arrow head Duck potato
Flowering Rush (non-native)
• Emergent plants typically have 1. Leaf has a thick waxy cuticle 2. Leaf and stems are rigid and comprised of spongy tissue and air spaces
• Floating Leaf Plants – plants with leaves floating at the surface of the water, may be attached to the substrate or unattached.
Water shield
European frogbit (non-native)
• Floating leaf plants typically have… 1. Tough and leathery due to a thick waxy cuticle 2. Circular or elliptical leaves with smooth margins 3. If a petiole is present its elastic, or has lots of slack 4. If petiole lacking, has rootlets
Water hyacinth
White water Lilly
• Submersed Plants – majority of biomass is below the surface. Some submersed plants have floating leaves associated with the flower.
Eel grass
Eurasian water milfoil (non-native)
• Submersed plants typically have… 1. Thin leaf, lacking a thick waxy cuticle 2. Leaves are flexible, decreasing resistance to water movement 3. Leaves are spongy and buoyant
Primary Keys for Aquatic Plant ID 2. Presence or absence of a Petiole • Petiolate = plant has a leaf stem • Sessile = no petiole present, leaf emerges directly from stem
Primary Keys for Aquatic Plant ID 3. Arrangement of leaves on the stem – Alternate Arrangement – one leaf arises from each node, alternating from side to side as you go up the stem
– Opposite arrangement – two leaves arise from each node, on opposite sides of the stem.
– Whorled arrangement – three or more leaves arise from each node, positioned around the stem
• Basal arrangement – all leaves emerge as a cluster from the bottom of the plant.
Primary Keys for Aquatic Plant ID 4. The architecture of the leaf blade • Simple Leaf – an undivided blade • Compound leaf – a fragmented blade
Primary Keys for Aquatic Plant ID 5. The edge of the leaf blade • Entire – leaf with a smooth margin • Sinuate – has little curves and wavy edges
• Dentate – has little teeth at the margin • Lobed – partially divided.
Primary Keys for Aquatic Plant ID 6. The shape of the leaf blade. • Elliptical – a stretched out oval • Lanceolate – gradually extending at the base and lessening at the apex
• Cordate – heart shaped • Linear – strap like, several times longer than wide
Primary Keys for Aquatic Plant ID 7. The veination of the leaf • Parallel – veins on the blade run parallel to each other • Pinnate - veins arranged along two sides of a central midvein
• Palmate – all veins emerge from a central point and radiate out.
Identification of Target Aquatic Invasive Plants well, some of them
Eurasian watermilfoil Myriophyllum spicatum
• Myrio (G) numberless, Phylo (G) leaf
• Spica (G) a spike
• Submerged • Compound leaf that is deeply divided • Whorled arrangement, 4 leaves per whorl • More than 12 leaflets per leaf • Apex of leaflet flat • Monecious flower on emergent spike • Red growing tip
Variable-leaf watermilfoil Myriophyllum heterophyllum
• Myrio (G) numberless, Phylo (G) leaf
• Hetero (G) different
• Submerged • Compound leaf, deeply divided • Whorled arrangement • Apex of leaf rounded • Very robust, stem thick and brown-red • Flower spike with whorled leaves that are lancelate and toothed
Milfoil “look-a-likes” • Coontail (Ceratophyllum species)
– leaflets distinctively forked – Non-rooted
• Bladderworts (Utricularia species)
– Leaflets branching – Carnivorous bladders present – Not rooted
Curly-leaf pondweed Potamogeton crispus
• Potamos (G) river, Geiton (G) neighbor • Crisp (L) curled
• • • •
Submerged Simple leaf Sessile Alternate arrangement • Leaves sinuate and dentate • Primary veins parallel.
Curly leaf pondweed “look-a-likes” • Many pondweeds have a similar appearance.
– Careful examination of wavy ridges and toothed margins make identification certain.
Hydrilla Hydrilla verticillata
• Hydro (G) water • Verticilla (L) a whorl of spindles
Hydrilla • Simple leaf • Sessile • Whorled arrangement (more than 4 leaves) • Leaves Lanceolate • Leaves dentate • Distinctive teeth on midrib
Hydrilla “look-a-likes” • Hydrilla looks similar to our native elodea species.
• Native elodea has whorls of three leaves, insignificant teeth.
Brazillian elodea Egeria densa
• Egeria (L) a nymph, • Dens (L) thick
Brazilian elodea • Simple leaf • Sessile • Whorled arrangement of 4 and bushy • Leaves Lanceolate • Leaves margin appears smooth • Distinctive teeth on midrib
Hydilla and Brazilian elodea all look very similar to our native elodea
Native elodea is VERY common If it has more than 3 leaves per whorl take note and collect a sample or photo.
European frogbit Hydrocharis morsus-ranae
• Hydro (G) water, Charis (G) compelling attractiveness, grace. • Rana (L) a frog
• Floating leaf plant • Leaves cordate and leathery • Leaves born as a rosette with long petioles • Produce stolon's • Wide sweeping veins • Flowers born signally, 3 white petals, yellow center
Frogbit “look-a-likes” • White water lilly (Nymphaea odorata)
• Water lilly = 1 leave from a single petiole, lacks stolen or free floating feathery roots. Flowers comprised of more than 3 petals
Water Chestnut Trapa natans
• Tapa(L) trap, Natant (L) swimming
• Rosette of floating fan shape leaves that are dentate • Each petiole has a distinct air bladder • Fruit is a large nut with 4 sharp spines
