Agrostis gigantea

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Redtop

Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Poales
Family: Poaceae
Genus: Agrostis
Species: A. gigantea
Binomial name
Agrostis gigantea
L.
Synonyms

Agrostis alba[1]

Agrostis gigantea, known by its common name Redtop, is a perennial plant of the Agrostis genus that can be distinguished from other Bent grasses by its colorful inflorescence during the blooming period and the width of its leaf blades. Other Bent grasses have an inflorescence that is green or grey during the blooming period and their leaf blades are more narrow.[1]

Contents

[edit] Description

Illustration of A. gigantea.
Illustration of A. gigantea.

Standing 2–4 feet (0.6–1.2 m) tall, the perennial Agrostis gigantea is green and unbranched. Each panicle is slender, hairless and round in cross-section. The leaf blades can be 8 inches (20 cm) long and 1/3 inch (1 cm) across, green, bluish green or grayish blue, linear in shape and flat. The sheath of each leaf is open and hairless; it has a tendency to split open into a deep V-shape. The node at the base of each sheath is purplish and hairless.[1] Lemmas are rarely awned.[2]

Rhizomes are less than 10 inches (25 cm) long and grow near to the surface, the deepest occurring at a depth of 6 inches (15 cm). Redtop intergrades with Creeping Bent grass (Agrostis stolonifera) since it is mostly erect culms and rhizomes, and creeping bent grass has mostly decumbent, stoloniferous culms.[2]

A. gigantea has been called an "attractive grass" when it is in bloom. When grown in large masses such as for agriculture, it can become a nuisance as a source of hayfever in early summer.[1]

Redtop regenerates vegetatively and by seed. Germination rates are high, generally 85 percent or greater. No pretreatment is necessary but light is required for germination. Redtop seeds are long-lived and accumulate in a seedbank. Germination was 91 percent after 6 years of storage and 50 percent after 20 years of storage in an uncontrolled environment.[2]

Sometimes used for prairie restorations; older stands of redtop may be replaced by forbs such as western yarrow (Achillea millefolium), goldenrod (Solidago spp.), common evening primrose (Oenothera biennis), common cinquefoil (Potentilla simplex), white sweetclover (Melilotus alba), and yellow sweetclover (Melilotus officinalis).[2]

[edit] Foodplant

The wind-pollinated flowers attract few insects. The caterpillars of several skippers feed on the foliage of Redtop, including Amblyscirtes vialis (Common Roadside Skipper), Hesperia leonardus (Leonard's Skipper), Hylephila phyleus (Fiery Skipper), and the introduced Thymelicus lineola (European Skipper). The caterpillars of the moth Leucania pseudargyria (False Wainscot) feed on Agrostis spp. (Bentgrasses). The seeds are eaten by the Field Sparrow to a limited extent, while the Cottontail rabbit occasionally browses on the foliage. Redtop is quite palatable to livestock.[1]

[edit] Distribution

Redtop, native to Europe, has been introduced throughout temperate North America as a pasture grass. It occurs from Newfoundland south to the mountains of northern Georgia and Alabama, west to California, and north to Alaska. The preference is full sun, moist to mesic conditions, and a loam or clay-loam soil. This grass adapts well to worn-out soil in agricultural fields.[1] It is apparently uncommon or absent from the warm, humid regions of the Gulf Coast and from the desert regions of the Southwest.[2] It has a circumpolar distribution, occurring as a now native grass in both North America and Eurasia.[1]

[edit] References

  1. ^ a b c d e f g John Hilty (23 November 2007). Redtop. Grasses, Sedges, and Non-Flowering Plants of Illinois. Retrieved on 2007-12-17. “Redtop is an attractive grass during its short period of bloom, otherwise it is rather ordinary looking. In areas where it is grown as an agricultural crop, it can become a significant source of hayfever during the early summer.”
  2. ^ a b c d e Carey, Jennifer H. (1995). Agrostis gigantea. Fire Effects Information System. Retrieved on 2007-12-13.

[edit] Gallery

A tuft of A. gigantea

A stand of tufts

A living ligula

Ligula display

[edit] External links