Achene—a dry, non-fleshy fruit that contains a single seed and does not break open when ripe.

Adventitious roots—roots originating above-ground on a stem and growing into the ground.

Allelopathic—producing chemicals that are toxic to or inhibit the growth of other plants.

Alternate—leaf arrangement in which a leaves emerges on alternating sides of the stem.

Annual—a plant whose entire life cycle occurs within one year.

Asexual reproduction—occurring without pollen transfer, typically vegetative reproduction.

Axil – the angle formed at the base of a leaf or stem and the stem that supports it.



Biennial—a plant that lives two years, flowering and setting seed in the second year.

Biomass— living or dead plant material

Bolting—rapid elongation of a shoot before flowering.

Bract—reduced leaf or petal-like structure at the base of a flower or inflorescence.

Bulb—fleshy underground shoot that stores carbohydrates and is capable of vegetative reproduction.



Cambium—a layer of living tissue found in the outermost growth ring, which should be severed when girdling a tree or shrub.

Cespitose – growing in tight groups; clumping. Also spelled Caespitose.

Compound leaf—a leaf composed of multiple leaflets.

Containment—a control strategy aimed at preventing the spread of an invasive species.

Cotyledon—the first juvenile leaves that emerge following seed germination.

CRBC—Clackamas River Basin Council.

CRISP—Clackamas River Invasive Species Partners, a collaborative group of land managers working to cooperatively combat invasive species in the Clackamas River watershed.

Crown—the top portion of the root from which leaves or shoots emerge.



Dicot—a flowering plant with two juveniles leaves (cotyledons) emerging following seed germination.

Dioecious—a plant with either female or male reproductive organs on a single individual.



EDRR—early detection and rapid response, is a weed management strategy that focuses on locating and treating weed populations before they become widespread.

Eradication—elimination of a species, including seeds, from a given area.



Fecundity—the reproductive rate of a species.

Floret—a small flower individual flower, commonly associated with grasses.

Foliar—application to the leaves of a plant.

Forb—any non-woody herbaceous, non grass-like plant.



Germination—the sprouting of a seed.

Gymnosperm—a group of seed baring plants that includes confiers.



Herbaceous—adjective describing non-woody plants.

Hybridize—interbreeding between different species or sub-species.



Inflorescence—a cluster of flowers on a plant.

Invasive plant—a non-native plant that exhibits rapid expansion that may adversely impact communities.







Lanceolate— a lance-shaped leaf, with the widest portion below the middle of the leaf, and longer than it is wide.

Lateral roots—underground roots spreading outward.

Leaflet—a small division of a compound leaf.

Lobe—rounded portion of a leaf



Monocot—a flowering plant with a single juveniles leaf (cotyledon) emerging following seed germination.

Mucronate-a rapidly tapering tip ending in short sharp point.



Native plant—a plant that evolved in its present location or dispersed to its present location unaided by humans.

Naturalized plant—a non-native plant species that is thoroughly established in its introduced range, and may have minimal impact.

NCUWC—North Clackamas Urban Watershed Council.

Nectar—a fluid secreted by many plants  to pollinators.

Nitrogen-fixing—a plant that utilizes soil bacteria or fungi to fix nitrogen gas into inorganic nitrogen compounds usable by plants.

Node—a joint, where leaves or branches join a stem.

Non-native plant—a plant found outside the evolved or historic range.



ODA—Oregon Department of Agriculture.

OISC—Oregon Invasive Species Council.

Opposite—leaf arrangement where two leaves emerge from on opposite sides of each node.



Panicle—an inflorescence structured as racemes that are themselves branched, extending from a central axis.

Perennial—a plant that lives more than one year.

Photosynthesis—the process by which plants produce sugars from water and carbon dioxide in the presence of chlorophyll using light energy.

Pinnate—Compound leaf with leaflets arranged opposite each other.

Plume—an feather-like inflorescence.

Pollination—transfer of pollen for fertilization and reproduction.

Propagule—a seed or vegetative part that could lead to the development of a new plant.





Raceme—a branched inflorescence arranged with flowers attached individually by small stalks to a central axis.

Rhizome—a horizontal stem growing below the soil surface which stores carbohydrates or serves for vegetative reproduction.

Riparian—related to streams or rivers.

Rootball—a large mass of a compact roots

Rosette—a cluster of leaves radiating from a central point, commonly associated with biennial plants in their first year.

Ruderal—a plant species that is commonly associated with disturbance.

Runner—an above ground root that spreads to form new plants.



SBVRC—Sandy Basin Vegetation Restoration Coalition, a collaborative group of land managers working to cooperatively combat invasive species in the Sandy River watershed.

Seedbank—viable seeds in the soil.

Serrate—saw-like leaf margin with teeth pointed forward.

Senescence—the late life or seasonal stages of a plant characterized by loss of above ground vigor or death.

Sexual reproduction—development of new plants from seed as a result of fertilization d by pollen.

Sheathed—surrounded or obscured by a leaf.

Shrub—a woody, often multi-stemmed plant.

Simple—undivided and not composed of multiple leaflets.

Spike—an inflorescence with unstalked flowers attached to a central axis.

Spikelet—a small spike; most commonly associated with grasses.

SRBWC—Sandy River Basin Watershed Council.

Stolon—a stem that creeps along the ground and reproduces by rooting at the nodes or tips.

Sucker—a shoot originating from below ground, commonly occurring on woody plants following cutting or mowing.



Taproot—a large vertical root, from which smaller roots emerge.

Terminal—at the end or tip.

Tiller—an erect shoot originating underground; or to reproduce vegetatively through tiller formation.

Toothed—leaf margin with outward facing teeth.



Umbel—a flat-topped or umbrella shaped inflorescence.



Vegetative reproduction—process by which new plants arise without sexual reproduction.

Viability—ability of a seed to germinate.












WeedWise Program