Chloridoideae is one of the largest subfamilies of

grasses 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 ...

, with roughly 150 genera and 1,600 species, mainly found in

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ar ...

tropical or subtropical

grasslands 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 natural ...

. Within 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 c ...

, their

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

are the

Danthonioideae Danthonioideae is a mainly southern hemisphere subfamily of grasses, containing the single tribe Danthonieae and one unplaced genus, with altogether roughly 300 species. It includes herbaceous to partially woody perennial or annual (less common) ...

. The subfamily includes widespread

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

s such as Bermuda grass (''

Cynodon dactylon ''Cynodon dactylon'', commonly known as Bermuda grass, is a grass found worldwide. It is native to Europe, Africa, Australia and much of Asia. It has been introduced to the Americas. Although it is not native to Bermuda, it is an abundant invasi ...

'') or goosegrass (''

Eleusine indica ''Eleusine indica'', the Indian goosegrass, yard-grass, goosegrass, wiregrass, or crowfootgrass, is a species of grass in the family Poaceae. It is a small annual grass distributed throughout the warmer areas of the world to about 50 degrees lat ...

''), but also

millet Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most species generally referred to as millets belong to the tribe Paniceae, but some millets al ...

species grown in some tropical regions, namely finger millet (''

Eleusine coracana ''Eleusine coracana'', or finger millet, also known as ragi in India, kodo in Nepal, is an annual herbaceous plant widely grown as a cereal crop in the arid and semiarid areas in Africa and Asia. It is a tetraploid and self-pollinating species p ...

'') and teff (''

Eragrostis tef ''Eragrostis tef'', also known as teff, Williams lovegrass or annual bunch grass, is an annual grass, a species of lovegrass native to the Horn of Africa, notably to both Eritrea and Ethiopia. It is cultivated for its edible seeds, also known as ...

''). With the exception of some species in ''

Ellisochloa ''Ellisochloa'' is a genus of Namibian and South African plants in the grass family. ; Species * '' Ellisochloa papposa'' (Nees) P.M.Peterson & N.P.Barker - Cape Province * '' Ellisochloa rangei'' (Pilg.) P.M.Peterson & N.P.Barker - Namibia See ...

'' and

, most of the subfamily's species use the C₄ photosynthetic pathway. The first evolutionary transition from C₃ to C₄ photosynthesis in the grasses probably occurred in this subfamily, around 32 to 25 million years ago in the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

Phylogeny

Relationships of tribes in the Chloridoideae according to a 2017

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

classification, also showing the Danthonioideae as sister group: The following genera have not been assigned to a tribe: *''

Gossweilerochloa ''Tridens'' is a genus of perennial grasses in the family Poaceae native to the Americas. ; Species * '' Tridens albescens'' (Vasey) Wooton & Standl. - southwest + south-central USA ( AZ NM TX LA AR OK KS), Mexico ( Chihuahua, Durango, ...

'' *''

Indopoa ''Indopoa'' is a genus of Indian plants in the Poaceae, grass family. The only known species is ''Indopoa paupercula'', native to the States of Maharashtra and Karnataka in India.Lepturopetium'' *''

Myriostachya ''Myriostachya'' is a genus of Asian plants in the grass family. The only known species is ''Myriostachya wightiana'', native to India, Bangladesh, Sri Lanka, Myanmar, Thailand, Sumatra, and Peninsular Malaysia Peninsular Malaysia ( ms, Sem ...

'' *''

Pogonochloa ''Pogonochloa'' is a genus of plants in the grass family. The only known species is ''Pogonochloa greenwayi'', native to Zambia and Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeas ...

'' *''

Pseudozoysia ''Pseudozoysia'' is a monotypic genus of plant in the grass family. The only known species is ''Pseudozoysia sessilis'', found only in Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣū ...

'' *''

Silentvalleya ''Silentvalleya'' is a genus of Indian plants in the grass family. ; Species * '' Silentvalleya chandwadensis'' Gosavi, B.R. Pawar & S.R. Yadav - near Chandwad in Maharashtra * '' Silentvalleya nairii'' V.J.Nair, Sreek., Vajr. & Bhargavan - L ...

References

* * Poaceae subfamilies {{Chloridoideae-stub