Panicoideae is the second-largest

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

of the

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 over 3,500 species, mainly distributed in warm temperate and tropical regions. It comprises some important agricultural crops, including

sugarcane Sugarcane or sugar cane is a species of (often hybrid) tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with ...

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

(or corn),

sorghum ''Sorghum'' () is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species is grown for grain, while many othe ...

, and

switchgrass ''Panicum virgatum'', commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55°N latitude in Canada southwards into the United States and Mexico. Switchgrass is one of the ...

. C₄ photosynthesis evolved independently a number of times in the subfamily, which presumably had a C₃ ancestor.

Description

The ligule has a fringe of hairs. The inflorescence is branched around a common axis. The spikelets are all alike with two bisexual florets that are joined below the glumes (the outer floral envelopes). The lower glume is shorter than the spikelet.

Systematics and taxonomy

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 ...

of grasses, the Panicoideae are sister to a clade made of the four subfamilies

Arundinoideae The Arundinoideae are a subfamily of the true grass family Poaceae with around 40 species, including giant reed and common reed. Unlike many other members of the PACMAD clade of grasses, the Arundinoideae all use C3 photosynthesis. Their sister ...

Chloridoideae Chloridoideae is one of the largest subfamilies of grasses, with roughly 150 genera and 1,600 species, mainly found in arid tropical or subtropical grasslands. Within the PACMAD clade, their sister group are the Danthonioideae. The subfamily inc ...

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) ...

, and

Micrairoideae Micrairoideae is a subfamily of the grass family Poaceae, distributed in tropical and subtropical regions. Within the PACMAD clade, it is sister to subfamily Arundinoideae. It includes roughly 190 species in nine genera. A phylogenetic classific ...

. A modern phylogenetic classification divides the Panicoideae in twelve

tribes The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to conflic ...

corresponding to

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

clades; two genera, ''

Chandrasekharania ''Chandrasekharania'' is a genus of Indian plants in the Poaceae, grass family.Nair, V. J., Ramachandran, V. S., & Sreekumar, P. V. 1982. Proceedings of the Indian Academy of Sciences 91(2): 79-80 The only known species is ''Chandrasekharania k ...

'' and ''

Jansenella ''Jansenella'' is a genus of Asian plants in the grass family. ; Species * '' Jansenella griffithiana'' (C.Muell.) Bor - India, Sri Lanka, Myanmar * '' Jansenella neglecta'' S.R.Yadav, Chivalkar & Gosavi - Maharashtra Maharashtra (; , abbr ...

'', are unplaced (''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'') but probably belong to tribe

Tristachyideae Tristachyideae is a tribe of the Panicoideae subfamily in the grasses (Poaceae), native to tropical and subtropical regions of Africa, Asia, and South America. There are around 70 species in eight genera. The tribe belongs to a basal lineage with ...

. The three largest tribes,

Paniceae Paniceae is a large tribe of the subfamily Panicoideae in the grasses (Poaceae), the only in the monotypic supertribe Panicodae. It includes roughly 1,500 species in 84 genera, primarily found in tropical and subtropical regions of the world. Pan ...

Paspaleae Paspaleae is a tribe of the Panicoideae subfamily in the grasses (Poaceae), native mainly to the tropical and subtropical Americas but with a number of species introduced to other regions. It includes roughly 680 species in 39 genera. Species in ...

, and

Andropogoneae The Andropogoneae, sometimes called the sorghum tribe, are a large tribe of grasses (family Poaceae) with roughly 1,200 species in 90 genera, mainly distributed in tropical and subtropical areas. They include such important crops as maize (corn), ...

, together with the small

Arundinelleae Arundinelleae is a tribe of grasses with roughly 90 species in three genera, mainly distributed in tropical and subtropical areas. The tribe's sister group are the Andropogoneae The Andropogoneae, sometimes called the sorghum tribe, are a larg ...

, form the core of the subfamily. The

Gynerieae ''Gynerium'' is a monotypic genus of Neotropical plants in the grass family, native to Mexico and Colombia, Central America, South America, and the West Indies. It is classified in its own tribe Gynerieae. The sole species in the genus is ''G ...

were formerly placed in Arundinoideae, and the basal lineage, the "centothecoid clade" with seven tribes, was formerly seen as separate subfamily, Centothecoideae. Phylogeny based on

chloroplast DNA Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nu ...

analyses, showing relationships of tribes within the subfamily (dashed lines indicate uncertain positions; C₄ clades flagged):

Gallery

File:Chasmanthium_latifolium_Boyle_Park.jpg, alt=Grass with large, flat spikelets, Woodoats (''

Chasmanthium latifolium ''Chasmanthium latifolium'', known as northern wood-oats, inland sea oats, northern sea oats, and river oats is a species of grass native to the central and eastern United States, Manitoba, and northeastern Mexico; it grows as far north as Pennsy ...

'',

Chasmanthieae Chasmanthieae is a small tribe of grasses in the subfamily Panicoideae Panicoideae is the second-largest subfamily of the grasses with over 3,500 species, mainly distributed in warm temperate and tropical regions. It comprises some important ...

) File:Flickr_-_João_de_Deus_Medeiros_-_Loudetiopsis_chrysothrix.jpg, alt=Dry grass spikelets, Spikelets of ''

Loudetiopsis chrysothrix ''Loudetiopsis'' is a genus of African and South American plants in the Poaceae, grass family.Jacques-Félix, Henri. 1960. Journal d'Agriculture Tropicale et de Botanique Appliquée 7: 408Conert, Hans Joachim. 1957. Botanische Jahrbücher für ...

'' (

) File:Gynerium_sagittatum_3.jpg, alt=Tall grass plants resembling cane, ''

Gynerium sagittatum ''Gynerium'' is a monotypic genus of Neotropical plants in the grass family, native to Mexico and Colombia, Central America, South America, and the West Indies. It is classified in its own tribe Gynerieae. The sole species in the genus is ''Gyn ...

'' File:Pennisetum villosum 002.jpg, alt=A feathery inflorescence of dense spikelets, Feathertop grass ('' Pennisetum villosum'',

) File:Corncobs.jpg, alt=Maize cobs in different colours, Cultivated maize or corn (''

Zea mays Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

'',

)

References

* * {{Taxonbar, from=Q1071663 Poaceae subfamilies