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.
"The most inclusive crown clade exhibiting the structural mutation in the plastid genome (loss of one copy of the ~25-kb inverted repeat region) homologous with that found in Galega officinalis, Glycyrrhiza lepidota, and Vicia faba, where these taxa are extant species included in the crown clade defined by this name."[3]
^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.