PACMAD clade

The PACMAD clade (previously PACCMAD, PACCAD, or PACC^[2]) 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.^[3]

PACMAD clade Temporal range: Campanian–Recent PreꞒ Ꞓ O S D C P T J K Pg N [1]
switchgrass (Panicum virgatum)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Clade:	Commelinids
Order:	Poales
Family:	Poaceae
Clade:	PACMAD clade
Subfamilies
Aristidoideae Arundinoideae Chloridoideae Danthonioideae Micrairoideae Panicoideae

Phylogeny

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:^[3]

Poaceae	Anomochlooideae Pharoideae Puelioideae BOP clade PACMAD clade Aristidoideae C3 & C4 Panicoideae C3 & C4 Chloridoideae C3 & C4 Danthonioideae C3 Arundinoideae C3 Micrairoideae C3 & C4