Alternate - leaves that are arranged
singly up the stem; not opposite each other.
Annual - plant that germinates, flowers, seeds,
and dies during one growing season.
Anther - structure in a flower in which pollen
Auricle - lobe-like structure at the collar of
a grass leaf.
Awn - slender bristle at the tip of grass seed
Axil - the angle formed between a leaf and a
Basal - at the base of a plant or plant part.
Biennial - plant that germinates in one growing
season, then flowers, seeds, and dies during a second.
Bract - leaf-like structure at the base of
flowers or leaves.
Calyx - all the flower leaves together,
normally green in color.
Clasping leaves - leaves that appear to wrap
around the stem at their base.
Compound leaves - leaves with 2 or more
Cotyledons - the first leaf-like structures
that appear after germination; seed leaves.
Crown - the structure formed where leaves,
stems, and roots grow together.
Dissected - deeply and repeatedly divided into
Entire - not toothed or otherwise cut.
Glumes - the 2 bracts surrounding a grass
Head - a group of flowers borne tightly
Leaflets - leaf-like structures within a
Ligule - the structure at the collar of a grass
leaf between the sheath and the stem.
Linear - long, narrow, and slender.
Lobed - a cut into a leaf from the edge toward
the center; greater than toothed, but not quite compound.
Margin - the edge of a leaf.
Membranous - thin and flexible, usually not
Midrib - the center and usually most prominent
vein on a leaf.
Nodding - a flower that is not pointed upward,
but bent downward or sidewise to the stem.
Opposite -leaves situated directly across the
stem from each other.
Ovate - egg shaped in outline.
Panicle - a much-branched inflorescence.
Perennial - a plant that lives for more than 2
Petiole - a leaf stalk.
Pinnate - with 2 rows of leaflets, like a
Plume - a hair-like or feather-like structure,
often on a seed.
Pubescence - the hairs on a leaf, stem or
Rhizome - a creeping, underground stem.
Rosette - a circular, normally basal, clump of
Sheath - the extension of leaf tissue
surrounding a stem.
Simple leaf- one with a blade
in one piece; not compound.
Spike - a narrow, non-spreading inflorescence.
Spikelet - a single or group of floral
structures in a grass.
Spur - a hollow appendage on a flower.
Stolon - a creeping stem along the surface of
Succulent - fleshy and juicy.
Taproot - a thick, central root with minimal
Trifoliate leaf - a leaf made of 3 leaflets;
Whorled -3 or more similar structured arranged
as spokes on a wheel.
© 1999 University of Idaho:
Text and photographs for these pages from Idaho's Noxious
Weeds, by Robert H. Callihan and Timothy W. Miller (revised
by Don W. Morishita and Larry W. Lass).
Please contact: Ag
Publishing, University of Idaho, Moscow, Idaho 83844-2240;
firstname.lastname@example.org; or visit the Resources for Idaho
for more information about this or other publications.