''Aristida'' is a very nearly
cosmopolitan
Cosmopolitan may refer to:
Food and drink
* Cosmopolitan (cocktail), also known as a "Cosmo"
History
* Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953
Hotels and resorts
* Cosmopoli ...
genus of plants in the
grass family. ''Aristida'' is distinguished by having three
awns (bristles) on each
lemma of each
floret
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...
. The genus includes about 300
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
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
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
"
arista", meaning "awn".
They are characteristic of
semiarid
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi- ...
grassland
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
. 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 ...
of
North America is named for ''
A. stricta''. Other locales where this genus is an important component of the
ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
include the
Carolina Bay
Carolina bays are elliptical to circular depressions concentrated along the Atlantic seaboard within coastal New York, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, and north Florida.Kaczorowski, R. T. (1977) '' ...
s, the
sandhills of
the Carolinas
The Carolinas are the U.S. states of North Carolina and South Carolina, considered collectively. They are bordered by Virginia to the north, Tennessee to the west, and Georgia to the southwest. The Atlantic Ocean is to the east.
Combining Nor ...
, and
elsewhere,
Mulga scrub in
Australia, and the
xeric
Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this h ...
grasslands around
Lake Turkana in
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. Local increases in the abundance of wiregrasses is a good indicator of
overgrazing
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature res ...
, as
livestock
Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animal ...
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
inflorescence
An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...
s may be either
panicle-like or
raceme-like, with spiky branches. The
glume
In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...
s 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:
See also
* ''
Puccinia aristidae'', a
plant pathogenic
urediniomycete fungus first described from three-awn grass
*
List of Poaceae genera
The true grasses (Poaceae) are one of the largest plant families, with around 12,000 species and roughly 800 genera. They contain, among others, the cereal crop species and other plants of economic importance, such as the bamboos, and several imp ...
References
{{Taxonbar, from=Q311128
Poaceae genera
Taxa named by Carl Linnaeus