''Aristida'' is a very nearly cosmopolitan genus of plants in the

grass family Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and ...

. ''Aristida'' is distinguished by having three

awn AWN may stand for: * Awn Access to Justice Network in Gaza Strip, Legal Aid Network operate in Gaza Strip, Palestine * Animation World Network, an online organization for animators * Avant Window Navigator, a dock-like bar that tracks open windows ...

s (bristles) on each

lemma Lemma may refer to: Language and linguistics * Lemma (morphology), the canonical, dictionary or citation form of a word * Lemma (psycholinguistics), a mental abstraction of a word about to be uttered Science and mathematics * Lemma (botany), a ...

of each floret. The genus includes about 300 species found worldwide, often in arid warm regions. This genus is among those colloquially called three-awns wiregrasses, speargrasses and needlegrasses. The name ''Aristida'' is derived from the Latin "

arista Arista may refer to: Organizations *Arista Networks, a software defined networking company *Arista Records, an American record label, division of Sony Music **Arista Nashville, a record label specializing in country music *Arista (honor society) ...

", meaning "awn". They are characteristic of semiarid grassland. The

Wiregrass Region The Wiregrass region or Wiregrass country is an area of the Southern United States encompassing parts of southern Georgia, southeastern Alabama, and the Florida Panhandle. The region is named for the native ''Aristida stricta'', commonly known a ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

is named for '' A. stricta''. Other locales where this genus is an important component of the ecosystem include the Carolina Bays, the sandhills of the Carolinas, and elsewhere, Mulga scrub in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, and the xeric grasslands around

Lake Turkana Lake Turkana (), formerly known as Lake Rudolf, is a lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. B ...

in Africa. Local increases in the abundance of wiregrasses is a good indicator of overgrazing, as livestock avoid them.

Description

''Aristida'' stems are ascending to erect, with both basal and cauline leaves. The leaves may be flat or inrolled, and the basal leaves may be tufted. The inflorescences may be either

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

-like or

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

-like, with spiky branches. The glumes of a spikelet are narrow lanceolate, usually without any awns, while the lemmas are hard, three-veined, and have the three awns near the tip. The awns may be quite long; in ''A. purpurea '' var. ''longiseta'' they may be up to 10 cm.

Species

Selected species include:

References

{{Taxonbar, from=Q311128 Poaceae genera Taxa named by Carl Linnaeus

Description

Species

See also

References