The Aristideae is the sole tribe of grasses in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

subfamily Aristidoideae of the true grass

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Poaceae. Its members are herbaceous annuals or

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

s found in the

tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referr ...

subtropic The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north and ...

s and

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

zones. The tribe has over 300 species in three genera: The subfamily is a member of the

PACMAD clade The PACMAD clade (previously PACCMAD, PACCAD, or PACC) is one of two major lineages (or clades) of the true grasses (Poaceae), regrouping six subfamilies and about 5700 species, more than half of all true grasses. Its sister group is the BOP cla ...

of grasses, the evolutionary group in which

C4 photosynthesis carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960's discovery by Marshall Davidson Hatch and Charles Roger Slack that some plants, when suppl ...

independently evolved a number of times.Phylogeny of the Paniceae (Poaceae: Panicoideae): integrating plastid DNA sequences and morphology into a new classification Osvaldo Morrone, Lone Aagesen, Maria A. Scataglini, Diego L. Salariato, Silvia S. Denham, Maria A. Chemisquy, Silvana M. Sede, Liliana M. Giussani, Elizabeth A. Kellogg and Fernando O. Zuloag Cladistics 28 (2012) 333–356 *''

Aristida ''Aristida'' is a very nearly cosmopolitan genus of plants in the grass family. ''Aristida'' is distinguished by having three awns (bristles) on each lemma of each floret. The genus includes about 300 species found worldwide, often in arid warm ...

'' *''

Sartidia ''Sartidia'' is a genus of Southern African and Madagascan plants in the grass family. It was split from '' Aristida'' in 1963 by South African botanist Bernard de Winter and contains six known species, of which '' Sartidia perrieri'' is conside ...

'' *'' Stipagrostis''

References

Aristidoideae Poaceae tribes {{Poaceae-stub