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The Info List - Basal Angiosperms


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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
Amborella
(a single species of shrub from New Caledonia), Nymphaeales (water lilies, together with some other aquatic plants) and Austrobaileyales
Austrobaileyales
(woody aromatic plants including star anise).[1] ANITA stands for Amborella, Nymphaeales
Nymphaeales
and I lliciales, Trimeniaceae-Austrobaileya.[2] Some authors have shortened this to ANA-grade for the three orders, Amborellales, Nymphaeales, and Austrobaileyales, since the order I lliciales was reduced to the family Illiciaceae
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.

Contents

1 Phylogeny 2 Older terms 3 References 4 External links

Phylogeny[edit]

Japanese star anise
Japanese star anise
(Illicium anisatum), from the Austrobaileyales

The exact relationships between Amborella, Nymphaeales
Nymphaeales
and Austrobaileyales
Austrobaileyales
are not yet clear. Although most studies show that Amborella
Amborella
and Nymphaeales
Nymphaeales
are more basal than Austrobaileyales, and all three are more basal than the mesangiosperms, there is significant molecular evidence in favor of two different trees, one in which Amborella
Amborella
is sister to the rest of the angiosperms, and one in which a clade of Amborella
Amborella
and Nymphaeales
Nymphaeales
is in this position.[3] A 2014 paper says that it presents "the most convincing evidence to date that Amborella
Amborella
plus Nymphaeales
Nymphaeales
together represent the earliest diverging lineage of extant angiosperms".[4]

Angiospermae

Amborella

Nymphaeales

Austrobaileyales

Mesangiospermae

Angiospermae

Amborella

Nymphaeales

Austrobaileyales

Mesangiospermae

Older terms[edit]

Amborella

Paleodicots (sometimes spelled "palaeodicots") is an informal name used by botanists (Spichiger & Savolainen 1997,[5] Leitch et al. 1998[6]) to refer to angiosperms which are not monocots or eudicots. 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. The "paleodicots" are not a monophyletic group and the term has not been widely adopted. The APG II system
APG II system
does not recognize a group called "paleodicots" but assigns these early-diverging dicots to several orders and unplaced families: Amborellaceae, Nymphaeaceae (including Cabombaceae), Austrobaileyales, Ceratophyllales
Ceratophyllales
(not included among the "paleodicots" by Leitch et al. 1998), Chloranthaceae, and the magnoliid clade (orders Canellales, Piperales, Laurales, and Magnoliales). Subsequent research has added Hydatellaceae
Hydatellaceae
to the paleodicots. The term paleoherb is another older term for flowering plants which are neither eudicots nor monocots.[7] References[edit]

^ 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  ^ 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: 404–407.  ^ Soltis, D. E.; Soltis, P. S. (2004), " Amborella
Amborella
not a "basal angiosperm"? Not so fast", American Journal of Botany, 91 (6): 997–1001, doi:10.3732/ajb.91.6.997, PMID 21653455  ^ Xi, Zhenxiang; Liu, Liang; Rest, Joshua S. & Davis, Charles C. (2014), "Coalescent versus concatenation methods and the placement of Amborella
Amborella
as sister to water lilies", Systematic Biology, 63 (6): 919–932, doi:10.1093/sysbio/syu055, PMID 25077515, retrieved 2015-09-13  ^ Rudolphe Spichiger & Vincent Savolainen. 1997. Present state of Angiospermae phylogeny. Candollea 52: 435-455 (text Archived 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, Botanical Society of America, 88 (4): 706–16, doi:10.2307/2657072, JSTOR 2657072, PMID 11302858 

External links[edit

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