The inverted repeat-lacking clade (IRLC) is a monophyleticclade of the flowering plant subfamily Faboideae (or Papilionaceae). Faboideae includes the majority of agriculturally-cultivated legumes. The name of this clade is informal and is not assumed to have any particular taxonomic rank like the names authorized by the ICBN or the ICPN.[3] The clade is characterized by the loss of one of the two 25-kb inverted repeats in the plastid genome that are found in most land plants.[6] It is consistently resolved in molecular phylogenies.[1][2][5][6][7][8][9][10][11][12][13] The clade is predicted to have diverged from the other legume lineages 39.0±2.4 million years ago (in the Eocene).[14] It includes several large, temperate genera such as Astragalus, Hedysarum, Medicago, Oxytropis, Swainsona, and Trifolium.
^Sanderson MJ, Wojciechowski MF (1996). "Diversification rates in a temperate legume clade: Are there "so many species" of Astragalus (Fabaceae)?". Am J Bot. 83 (11): 1488–1502. doi:10.2307/2446103. JSTOR2446103.
^Cardoso D, de Queiroz LP, Pennington RT, de Lima HC, Fonty É, Wojciechowski MF, Lavin M (2012). "Revisiting the phylogeny of papilionoid legumes: New insights from comprehensively sampled early-branching lineages". Am J Bot. 99 (12): 1991–2013. doi:10.3732/ajb.1200380. PMID23221500.