PACMAD clade

The PACMAD clade (previously PACCMAD, PACCAD, or PACC[1]) 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 clade. The PACMAD lineage is the only group within the grasses in which the C4 photosynthesis pathway has evolved; studies have shown that this happened independently multiple times.[2]

PACMAD clade
Panicum virgatum.jpg
switchgrass (Panicum virgatum)
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Clade: PACMAD clade

The name of the clade comes from the first initials of the included subfamilies Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, and Danthonioideae. It has no defined taxonomic rank but is used frequently because it refers to a well-defined monophyletic group with a distinct ecology.

Phylogeny of the PACMAD clade, with photosynthetic pathways for each subfamily:[2]





BOP clade

PACMAD clade

Aristidoideae C3 & C4

Panicoideae C3 & C4

Chloridoideae C3 & C4

Danthonioideae C3

Arundinoideae C3

Micrairoideae C3 & C4


  1. ^ Soreng, Robert J.; Peterson, Paul M.; Romaschenko, Konstantin; Davidse, Gerrit; Zuloaga, Fernando O.; Judziewicz, Emmet J.; Filgueiras, Tarciso S.; Davis, Jerrold I.; Morrone, Osvaldo (2015). "A worldwide phylogenetic classification of the Poaceae (Gramineae)". Journal of Systematics and Evolution. 53 (2): 117–137. doi:10.1111/jse.12150. ISSN 1674-4918. S2CID 84052108.  
  2. ^ a b Grass Phylogeny Working Group II (2012). "New grass phylogeny resolves deep evolutionary relationships and discovers C4 origins". New Phytologist. 193 (2): 304–312. doi:10.1111/j.1469-8137.2011.03972.x. hdl:2262/73271. ISSN 0028-646X. PMID 22115274.