PACMAD clade
The PACMAD clade is one of two major lineages of the true grasses, 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 within which the C4 photosynthesis pathway has evolved; studies have shown that this happened independently multiple times.
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:
