J Syst Evol ›› 2022, Vol. 60 ›› Issue (3): 522-569.DOI: 10.1111/jse.12857

• Research Articles • Previous Articles     Next Articles

Grasses through space and time: An overview of the biogeographical and macroevolutionary history of Poaceae

Timothy J. Gallaher1*, Paul M. Peterson2, Robert J. Soreng2, Fernando O. Zuloaga3, De‐Zhu Li4,5, Lynn G. Clark6, Christopher D. Tyrrell7 , Cassiano A.D. Welker8, Elizabeth A. Kellogg9, and Jordan K. Teisher10   

  1. 1 Department of Natural Science, Herbarium Pacificum, Bishop Museum, 1525 Bernice St., Honolulu, HI 96817, USA
    2 Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013‐7012, USA
    3 Instituto de Botánica Darwinion (CONICET‐ANCEFN), Labardén 200, Casilla de Correo 22, San Isidro B1642HYD, Buenos Aires, Argentina
    4 Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
    5 University of Chinese Academy of Sciences, Beijing 100049, China
    6 Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
    7 Botany Department, Milwaukee Public Museum, 800 W Wells Street, Milwaukee, WI 53233, USA
    8 Instituto de Biologia, Universidade Federal de Uberlândia, Rua Ceará s/n, 38400‐902, Uberlândia, MG, Brazil
    9 Donald Danforth Plant Science Center, St Louis, MO 63132, USA
    10Missouri Botanical Garden, 4344 Shaw Blvd, St. Louis, MO 63110, USA

    *Author for correspondence.
    E‐mail: timothy.gallaher@bishopmuseum.org
  • Received:2021-08-01 Accepted:2022-04-19 Online:2022-04-27 Published:2022-05-01


Grasses are widespread on every continent and are found in all terrestrial biomes. The dominance and spread of grasses and grassland ecosystems have led to significant changes in Earth′s climate, geochemistry, and biodiversity. The abundance of DNA sequence data, particularly chloroplast sequences, and advances in placing grass fossils within the family allows for a reappraisal of the family′s origins, timing, and geographic spread and the factors that have promoted diversification. We reconstructed a time-calibrated grass phylogeny and inferred ancestral areas using chloroplast DNA sequences from nearly 90% of extant grass genera. With a few notable exceptions, the phylogeny is well resolved to the subtribal level. The family began to diversify in the Early–Late Cretaceous (crown age of 98.54 Ma) on West Gondwana before the complete split between Africa and South America. Vicariance from the splitting of Gondwana may be responsible for the initial divergence in the family. However, Africa clearly served as the center of origin for much of the early diversification of the family. With this phylogenetic, temporal, and spatial framework, we review the evolution and biogeography of the family with the aim to facilitate the testing of biogeographical hypotheses about its origins, evolutionary tempo, and diversification. The current classification of the family is discussed with an extensive review of the extant diversity and distribution of species, molecular and morphological evidence supporting the current classification scheme, and the evidence informing our understanding of the biogeographical history of the family.

Key words: ancestral area estimation, dispersal, Gondwana, historical biogeography, molecular dating, vicariance