Glossary

  • 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 is formed
  • Auricle - lobe-like structure at the collar of a grass leaf
  • Awn - slender bristle at the tip of grass seed structures
  • Axil - the angle formed between a leaf and a stem
  • 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 distinct leaflets
  • 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 smaller parts
  • Entire - not toothed or otherwise cut
  • Glumes - the 2 bracts surrounding a grass spikelet
  • Head - a group of flowers borne tightly together
  • Leaflets - leaf-like structures within a compound leaf
  • 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 green
  • Midrib - the center and usually most prominent vein on a leaf
  • Nodding - a flower that is not pointed upward, but bent downward or sideways 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 growing seasons.
  • Petiole - a leaf stalk
  • Pinnate - with 2 rows of leaflets, like a feather
  • Plume - a hair-like or feather-like structure, often on a seed
  • Pubescence - the hairs on a leaf, stem or flower
  • Rhizome - a creeping, underground stem
  • Rosette - a circular, normally basal, clump of leaves
  • 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 the ground
  • Succulent - fleshy and juicy
  • Taproot - a thick, central root with minimal branching
  • Trifoliate leaf - a leaf made of 3 leaflets; clover-like
  • 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 to 2240; 208-882-7982 visit the Resources for Idaho website for more information about this or other publications.