The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade, which is made up of Amborella (a single species of shrub from New Caledonia), Nymphaeales (water lilies, together with some other aquatic plants) and Austrobaileyales (woody aromatic plants including star anise).[1]
ANITA stands for Amborella, Nymphaeales, Illiciales, Trimeniaceae, and Austrobaileya.[2] Some authors have shortened this to ANA-grade for the three orders, Amborellales, Nymphaeales, and Austrobaileyales, since the order Iliciales was reduced to the family Illiciaceae and placed, along with the family Trimeniaceae, within the Austrobaileyales.
The basal angiosperms are only a few hundred species, compared with hundreds of thousands of species of eudicots, monocots, and magnoliids. They diverged from the ancestral angiosperm lineage before the five groups comprising the mesangiosperms diverged from each other.
Paleodicots (sometimes spelled "palaeodicots") is an informal name used by botanists (Spichiger & Savolainen 1997,[4] Leitch et al. 1998[5]) to refer to angiosperms which are not monocotsoreudicots.
The paleodicots correspond to Magnoliidae sensu Cronquist 1981 (minus Ranunculales and Papaverales) and to Magnoliidae sensu Takhtajan 1980 (Spichiger & Savolainen 1997). Some of the paleodicots share apparently plesiomorphic characters with monocots, e.g., scattered vascular bundles, trimerous flowers, and non-tricolpate pollen.
^Thien, L. B.; Bernhardt, P.; Devall, M. S.; Chen, Z.-d.; Luo, Y.-b.; Fan, J.-H.; Yuan, L.-C.; Williams, J. H. (2009), "Pollination biology of basal angiosperms (ANITA grade)", American Journal of Botany, 96 (1): 166–182, doi:10.3732/ajb.0800016, PMID21628182
^Yin-Long Qiu; Jungho Lee; Fabiana Bernasconi-Quadroni; Douglas E. Soltis; Pamela S. Soltis; Michael Zanis; Elizabeth A. Zimmer; Zhiduan Chen; Vincent Savolainen; Mark W. Chase (1999). "The earliest angiosperms: Evidence from mitochondrial, plastid and nuclear genomes". Nature. 402 (6760): 404–407. Bibcode:1999Natur.402..404Q. doi:10.1038/46536. PMID10586879. S2CID4380796.
^Rudolphe Spichiger & Vincent Savolainen. 1997. Present state of Angiospermae phylogeny. Candollea 52: 435-455 (textArchived March 12, 2007, at the Wayback Machine)
^Leitch, I. J., M. W. Chase, and M. D. Bennett. 1998. Phylogenetic analysis of DNA C-values provides evidence for a small ancestral genome size in flowering plants. Annals of Botany 82 (Suppl. A): 85-94.
^Jaramillo, M. Alejandra; Manos, PS (2001), "Phylogeny and Patterns of Floral Diversity in the Genus Piper (Piperaceae)", American Journal of Botany, 88 (4), Botanical Society of America: 706–16, doi:10.2307/2657072, JSTOR2657072, PMID11302858
