''Tridens flavus'', known as purpletop, purpletop tridens, tall redtop, greasy grass, and grease grass, is a large, robust

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

bunchgrass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennia ...

. The seeds are purple, giving the grass its common name. The seeds are also oily, leading to its other common name, "grease grass". It reproduces by seed and tillers. The grass is often confused with the similar looking

Johnson grass Johnson grass or Johnsongrass, ''Sorghum halepense'', is a plant in the grass family, Poaceae, native to Asia and northern Africa. The plant has been introduced to all continents except Antarctica, and most larger islands and archipelagos. It re ...

(''Sorghum halepense''), although it is only distantly related. ''Tridens flavus'' is easily distinguished by its short, hairy

ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above g ...

. Native to eastern North America, it is widespread throughout its range and is most often found in man-made habitats, such as hay meadows and lawns. It is a larval host to the common wood nymph,

crossline skipper ''Polites origenes'', the crossline skipper,
funet.fi

, little glassywing, and the

Zabulon skipper The Zabulon skipper (''Lon zabulon'') (sometimes called the southern dimorphic skipperJames A. Scott (1986). ''The Butterflies of North America''. Stanford University Press, Stanford, CA. ) is a North American butterfly first described by the ...

.The Xerces Society (2016), ''Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects'', Timber Press.

Gallery

References

External links

Samuel Roberts Noble Foundation

* Chloridoideae Bunchgrasses of North America Plants described in 1753 Taxa named by Carl Linnaeus {{Chloridoideae-stub