Andropogoneae

Andropogoneae
Name	Andropogoneae
Regnum	Plantae
Clade	Angiosperms
Clade2	Monocots
Ordo	Poales
Familia	Poaceae
Subfamilia	Panicoideae
Tribus	Andropogoneae

Andropogoneae is a tribe of Poaceae notable for many economically and ecologically important grasses such as Zea mays, Sorghum bicolor, Saccharum officinarum, and Miscanthus giganteus. Members are widespread across Africa, Asia, the Americas, and Australia, dominating savannas, grasslands, and agricultural systems and influencing landscapes from the Serengeti to the Great Plains. The group has been central to human societies through crops, bioenergy, and forage and is a focus of research in systematics, paleobotany, and agronomy.

Taxonomy and classification

Andropogoneae is placed within Panicoideae of Poaceae with affinities to tribes such as Paniceae and Paspaleae and has been circumscribed through morphological work by botanists like George Bentham and molecular phylogenetics led by researchers from institutions including Kew Gardens and the Smithsonian Institution. Taxonomic revisions incorporate molecular markers (nrDNA ITS, plastid ndhF) used in studies by teams at University of California, Davis, University of Illinois Urbana–Champaign, and Commonwealth Scientific and Industrial Research Organisation. The tribe contains numerous subtribes and genera recognized in floras of Flora of China, Flora Europaea, and regional treatments from the Royal Botanic Gardens, Kew and the United States Department of Agriculture.

Morphology and distinguishing features

Members typically exhibit paired spikelets—one sessile and fertile, one pedicellate and often sterile—and inflorescences that form racemes or panicles, characters emphasized in monographs from Royal Botanic Gardens, Kew and field guides used in Kew Herbarium collections. Diagnostic anatomical traits include C4 photosynthetic anatomy (NADP-ME, NAD-ME types), as documented in studies at Max Planck Institute for Plant Breeding Research and Wageningen University & Research, and structural features such as glumes, awns, and ligules cited in the International Plant Names Index and regional floras of Australia and South Africa. Comparative morphology has been central to classification efforts by taxonomists at Missouri Botanical Garden and historical descriptions in works by Carl Linnaeus and Aimé Bonpland.

Distribution and habitat

The tribe has a cosmopolitan distribution with centers of diversity in tropical Africa, South America, and Southeast Asia, and important radiations in Madagascar and the Indian subcontinent. Species occupy habitats from seasonally flooded floodplains studied in the Amazon Basin to fire-prone savannas like the Kruger National Park and anthropogenic habitats such as rice paddies and sugarcane plantations spanning Brazil, India, and Thailand. Biogeographic patterns have been analyzed using datasets from GBIF and palaeoclimatic reconstructions involving the Intergovernmental Panel on Climate Change scenarios.

Ecology and interactions

Andropogoneae species drive fire regimes in ecosystems like the North American prairie and the African savanna and are keystone primary producers supporting herbivores such as Bison bison, Syncerus caffer, and Phacochoerus africanus. They host specialized herbivores and mutualists including Diatraea saccharalis on Saccharum, pollinators involved in pollen transfer studies at Smithsonian Tropical Research Institute, and endophytic fungi investigated by labs at Pennsylvania State University and CIRAD. Interactions with invasive plants and pests, and responses to El Niño–Southern Oscillation events, have been a focus in research by CSIRO and the International Maize and Wheat Improvement Center.

Economic importance and uses

The tribe includes staple and cash crops: Zea mays (maize), Sorghum bicolor (sorghum), Saccharum officinarum (sugarcane), Sorghum halepense (Johnson grass as weed), and bioenergy candidates like Miscanthus giganteus and Panicum virgatum (switchgrass). These genera underpin industries in United States Department of Agriculture reports, commodities markets such as the Chicago Board of Trade, and global trade networks centered in Brazil, United States, China, and India. Uses range from food and animal forage in systems managed by the Food and Agriculture Organization to cellulose-based biofuel research at National Renewable Energy Laboratory and breeding programs at institutions like CIMMYT and ICRISAT.

Phylogeny and evolutionary history

Molecular phylogenies based on plastid and nuclear genes place the tribe within a C4-dominated clade that diversified during the late Miocene and Pliocene, paralleling global cooling and expansion of open habitats reported in palaeobotanical syntheses from Royal Society publications and the National Science Foundation. Fossil phytolith records from sites in Argentina, Africa, and Asia inform timing of C4 evolution, with synthesis papers by researchers affiliated with University of Oxford and Harvard University integrating molecular clock analyses. Adaptive radiations coincide with the evolution of traits facilitating grazing tolerance and fire resilience documented in ecological syntheses from The Nature Conservancy and long-term datasets from Long Term Ecological Research Network sites.

Notable genera and species

Prominent genera include Zea (maize), Sorghum (sorghum), Saccharum (sugarcane), Miscanthus, Sarga, Alloteropsis, Echinochloa (barnyard grasses), Andropogon (bluestems), Themeda (kangaroo grass), Chrysopogon, Imperata (including Imperata cylindrica), Bothriochloa, Paspalum, Sorghastrum, Heteropogon, Pennisetum (including movements related to Pennisetum glaucum), Panicum (including Panicum virgatum), and Arthraxon. Economically critical species such as Zea mays, Sorghum bicolor, Saccharum officinarum, and Miscanthus giganteus are subjects of breeding and genetic research at centers including USDA ARS, CIMMYT, and university programs at Iowa State University and University of Nebraska–Lincoln.

Category:Poaceae