GLOSSARY OF TERMS
A • B • C • D • E • F • G • H • I • J• K• L • M • N • O • P • Q• R • S • T • U• V • W • X• Y• Z




 A

  • Annual
    A plant starting from seed and completing its life cycle in the same growing season.
  • Auricle
    Hornlike or clawlike appendage projecting from the base of the leafblade or from the sheath apex; occurs in pairs to each side.
  • Awn
    A bristlelike structure, usually extending from (attached to) the glumes of lemma of grasses.



B

  • Biennial
    A plant starting from seed and requiring two years to complete its life cycle.
  • Blade
    Expanded portion of a leaf; the flat portion of a grass leaf above the sheath.
  • Blend, seed
    A combination of two or more cultivars of a single species.
  • Bunch type growth
    Plant development by intravaginaI tillering at or near the soil surface, without production of rhizomes or stolons.



C

  • Caryopsis
    Dry, indehiscent fruit in which the single ovule wall is adhered to the pericarp: as seed in grasses.
  • Coleoptile
    A sheathlike structure covering the shoot of grass seedlings.
  • Cool-season turfgrass
    Turfgrass species best adapted to growth during cool, moist periods of the year; commonly having temperature optimums of 15 to 24 degrees C (60 to 75 degrees F).
  • Creeping growth habit
    Extravaginal stem growth at or near the soil surface which results in lateral spreading by rhizomes and/or stolons.
  • Crown
    That portion of the grass plant which includes the stem apex, the unelongated internodes, and the lower nodes from which adventitious root are initiated.
  • Cutting height
    Of a mower, the distance between the plane of travel (base of wheel, roller, or skid) and the parallel plane of cut.



D

  • Dethatch
    Remove an excessive thatch accumulation either (a) mechanically, as by vertical cutting, or (b) biologically, as by topdressing with soil.



E

  • Embryo
    That portion of a seed that develops into a young plant.
  • Endosperm
    That portion of a seed that contains reserve foods.



F

  • Fluorescence Test
    A test conducted on ryegrass seed that indicated the presence of annual ryegrass in perennial seed lots. The roots of annual ryegrass glow on white filter paper under the ultraviolet light.



G

  • Glume
    One of the pair of outer bracts at the base of a spikelet.



H

  • Hybrid
    The progeny resulting from a cross of individuals that differ in one or more heritable characters.



I

  • Inflorescence
    The flowering part of a plant.
  • Interseeding
    Seeding the same species into an existing turf with a more desirable variety to improve the stand of turf.



L

  • Lemma
    The bract within a spikelet enclosing the germ side of a floret. A bract above the pair of glumes.
  • Ligule
    A thin, often scarious projection from the summit of the leaf sheath in grasses; may be a membrane, a fringe of hairs, or absent.



M

  • Mixture, seed
    A combination of seeds of two or more species.



N

  • Noxious weed
    Each state has a list of weeds that are considered noxious in their state. Gener ally these weeds are particularly trouble some in turf. All noxious Weeds present in a seed lot must be shown on the seed label if they are listed as noxious in a particular state.



O

  • Overseeding
    Seeding into an existing turf. See also winter overseeding.
  • Ovule
    Structure that, when fertilized, develops into a seed.



P

  • Palea
    The inner bract of a floret; the bract enclosing the crease side of a kernel or the bract opposite the lemma.
  • Perennial plant
    A plant that may or may not start from seed, may or may not produce seed, and requires more than two years to complete its life cycle.
  • Pregermination
    Preconditioning of seed prior to planting by placing it in a moist, oxygenated environment at optimum temperature to favor more rapid germination after seeding.
  • Putting green
    The area of the hole being played that is specially prepared for putting or otherwise defined as such by the committee. A ball is deemed to be on the putting green when any part of it touches the putting green. Putting greens are mowed between .09 to 0.14 thousands inch (3.54 to 8 millimeters), depending on the quality desired.



R

  • Rachilla
    The main axis of a grass spikelet; the stem of a floret.
  • Renovation, turf
    Improvement usually involving weed control and replanting into existing live and/or dead vegetation; does not encompass reestablishment.
  • Reseeding, turf
    To seed again, usually soon after an initial seeding has failed to achieve satisfactory establishment.
  • Rhizome
    A jointed, underground stem that can produce roots and shoots at each node; may originate from the main stem or from tillers.



S

  • Seed
    The entire structure developed from the ovule after fertilization; a mature ovule.
  • Sheath
    Basal tubular portion of a leaf surrounding the stem.
  • Sod strength
    The relative ability of sod to resist tearing during harvesting, handling. and transplanting; in research, the mechanical force (newtons) required to tear apart a sod when subjected to a uniformly applied force.
  • Sodding
    Planting turf by laying sod.
  • Stolon
    A jointed, above-ground, creeping stem that can produce roots and shoots at each node and may originate extravaginally from the main stem of tillers.



T

  • Texture
    In turf, the composite leaf width, taper, and arrangement.
  • Thatch
    An intermingled organic layer of dead and living shoots, stems, and roots that develops between the zone or green vegetation and the soiI surface.
  • Topdressing
    A prepared soil mix added to a turf surface and usually physically worked in by matting, raking. and/or irrigating to smooth a surface.
  • Transitional climatic zone
    The suboptimal zone between the cool and warm climates where both warm - and cool- season grasses can be grown.
  • Turfgrass color
    The composite visual color of a turfgrass community perceived by the human eye.
  • Turfgrass quality
    The degree to which a turf conforms to an agreed standard of uniformity, density, texture, growth habit, smoothness, and color, as judged by subjective visual assessment.
  • Turfgrass uniformity
    The degree to which a turfgrass community is free from variations in color, density, and texture across the surface, as judged by visual assessment.



V

  • Variety
    A division of a species.



W

  • Warm-season turfgrass
    Turfgrass species best adapted to growth during the warmer part of the year; usually dormant during cold weather or injured by it; commonly having temperature optimum of 27 to 35 degrees C (80 to 95 degrees F); e.g., bahiagrass, bermudagrass, St. Augustinegrass, and zoysiagrass.
  • Winter overseeding
    Seeding cool-season turfgrasses onto warm-season turfgrasses at or near their start of winter dormancy; used in mild climates to provide green, growing turf during the winter period when the warm-season species are brown and dormant.