Weed Identification Field Guide
Glossary
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- Achene
- A dry, one-seeded fruit that does not open or split. Top
- Alternate
- Leaves spaced singly along a stem, with one leaf at
each node. Top
- Annual
- A plant that completes its life cycle during a single
growing season. Top
- Auricle
- A claw-like or clasping appendage at the base of a grass
leaf blade where it meets the sheath (near the collar). Top
- Awn
- A narrow, stiff bristle occurring at the end or edge of a
plant organ. Top
- Axil
- The area where the stem and leaf meet. Top
- Axillary
- Positioned in or rising from an axil (for example, axillary
buds). Top
- Basal
- Positioned at or near the base of a structure. Top
- Biennial
- A plant that requires two years to complete its life cycle. Top
- Blade
- The elongated, extended and flattened part of a leaf. Top
- Bolt
- To produce a stem from a basal rosette by rapid elongation. Top
- Bract
- A reduced leaf or leaf-like structure at the base of a flower
or flower cluster. Top
- Bristle
- A short, stiff hair or hair-like structure. Top
- Bulb
- An underground stem with fleshy, thick storage leaves
or scales. Top
- Calyx
- The outermost whorl of flower parts, usually green sepals
that cover other flower parts in the bud. Top
- Collar
- The area of a grass leaf at the junction of the blade
and sheath. Top
- Compound
- Consisting of two or more parts united in a single
structure. For example, a compound leaf is divided into two or
more distinct leaflets. Top
- Cotyledon
- The first leaf or leaves of a newly emerging plant, also
called seed leaves. Top
- Creeping perennial
- A perennial that can reproduce and spread
vegetatively.Decumbent- Horizontal or laying flat for most of the length with
only the tip ascending. Top
- Disk (flower)
- Tubular flowers in the center of a flower head, characteristic
of the sunflower family. Top
- Elliptic
- Oval-shaped, but tapering at both ends. Top
- Entire
- A continuous, untoothed margin. Top
- Hypocotyl
- The stem of a young seedling below the cotyledon(s). Top
- Inflorescence
- A cluster of flowers. Top
- Integrated weed management
- Combines different management strategies such as cultural, mechanical and chemical
methods to adjust to changing weed problems and weed
population shifts. Top
- Internode
- The area of a stem between successive nodes. Top
- Lanceolate
- A long, narrow shape that is widest at the base and
tapers to a tip. Top
- Leaflet
- One part of a compound leaf. Top
- Ligule
- In grasses, a thin membrane or ring of hairs at the junction
of the leaf sheath and blade on the inside of the leaf collar. Top
- Linear
- Long and narrow with parallel sides. Top
- Lobe
- A rounded segment of a plant part. Top
- Margin
- The edge or border of a plant part. Top
- Mealy
- Covered with material that resembles meal in texture. Top
- Midrib or midvein
- The central vein of a leaf. Top
- Nodding
- Drooping or bending over and downward. Top
- Node
- Joint in a stem where leaves and branches emerge. Top
- Noxious weed
- Weeds classified under the Iowa Weed Law. The law gives each county the authority to order the destruction of weeds classified as noxious by the state. Top
- Oblong
- Having an elongated, rounded shape, like a rectangle
with rounded corners. Top
- Ocrea
- A papery sheath that encloses the stem at the nodes, characteristic of the smartweed family. Top
- Opposite
- Leaves growing in pairs, two at each node on the stem. Top
- Ovate
- Having an oval outline; egg-shaped. Top
- Palmate
- Lobed, divided or veined from a common point like the
fingers of a hand. Top
- Panicle
- Seedhead with a main axis and subdivided branches;
may be compact or open. Top
- Pappus
- A cluster of hairs, bristles or scales that crown the top of
achenes and aid wind dispersion of seeds of some species in the
sunflower family. Top
- Pedicel
- The stalk of a spikelet or individual flower in an
inflorescence. Top
- Perennial
- A plant that lives for more than two years. Top
- Petiole
- The stalk between the leaf blade and the stem. Top
- Pinnate
- A compound leaf arrangement with leaflets occurring
on opposite sides of an elongated axis. Top
- Prostrate
- Lying on the ground. Top
- Raceme
- An inflorescence where the spikelets or flowers are on
stalks coming off a central axis or stem. Top
- Ray (flower)
- Strap-shaped flowers of some members of the
sunflower family. Top
- Rhizome
- A creeping, underground stem that can vegetatively
generate new growth. Top
- Rosette
- A circular cluster of leaves radiating from a stem where
the internodes have not elongated. A rosette appears as a circular
fan of leaves on the ground. Top
- Sepal
- A portion of the calyx; usually green but may look like
petals. Top
- Sessile
- A leaf or flower attached directly to another structure;
without a petiole or pedicel. Top
- Sheath
- Lowest part of the leaf that encloses the stem of grass
plants; a structure that surrounds another plant structure. Top
- Shoot
- New plant growth that can include stems, flower buds
and leaves. Top
- Simple
- A single plant structure that is unbranched or undivided. Top
- Simple perennial
- A perennial that reproduces only by seed. Top
- Spike
- An elongated, unbranched seedhead. Top
- Spikelet
- A small or secondary spike composed of one to several
flowers, characteristic of grasses and sedges. Top
- Stipules
- Small, often leaf-like appendages arising from the petiole
near the leaf base in some plants; may be modified to spines. Top
- Stolon
- An aboveground, modified stem that roots at the nodes
giving rise to new plants. Top
- Succulent
- Soft or fleshy. Top
- Summer annual
- A plant that germinates in the spring or summer
and completes its life cycle before winter. Top
- Taproot
- The main root, growing almost vertically downward,
from which small, lateral roots spread out. Top
- Tendril
- A slender, cylindrical modified leaf or stem that twists or
coils around a supporting structure. Top
- Terminal
- The tip or end of a stem or leaf. Top
- Tiller
- A shoot arising from a bud at the base of the plant. Top
- Toothed
- A projecting or divided part of a plant; jagged row on
the edge of a leaf or flower. Top
- Tuber
- A short, thickened portion of an underground stem;
provides food storage for the plant. Top
- Tubercle
- A small projection or bump on the surface of a
plant structure. Top
- Umbel
- A flat-topped or rounded inflorescence with branches
that come out from a common point. Top
- Wavy
- Having undulating and wavelike curves. Top
- Whorl
- A ring of three or more structures at a single node. Top
- Winter annual
- A plant that germinates in the early fall to early
spring, flowers, produces seed in mid-to late spring, then dies. Top
