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#angiosperm phylogeny

2 public questions tagged with this topic.

Plant Classification

The most basal angiosperm clade among the following is

Molecular clock analyses and phylogenomic datasets place ANA grade as earliest diverging extant angiosperm branches successive sisters to Mesangiospermae containing all other flowering plants representing about 99.95 percent diversity. Monocots diverge after Austrobaileyales within mesangiosperms, eudicots later forming large clade, magnoliids sister to monocot-eudicot clade forming magnoliids group. Therefore most basal among options remains ANA grade encompassing Amborella, Nymphaeales, Austrobaileyales. This basal position confirmed by plastid genome inversions and mitochondrial gene losses and nuclear single-copy gene phylogenies. Recognition refutes hypothesis magnoliids basal, highlighting importance of phylogenomic rooting using gymnosperm outgroups like Pinus Ginkgo.

Ref: APG IV 2016, Botanical Journal Linnean Society, ANA grade basal angiosperm phylogeny

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Plant Classification

The earliest diverging living angiosperm lineage is

Plastid phylogenomics incorporating rbcL, atpB, matK plus mitochondrial nad and nuclear concatenated genes robustly resolves Amborella trichopoda, shrub endemic New Caledonia with creamy white flowers spirally arranged, as earliest diverging living angiosperm sister to all others with maximal bootstrap support 100 percent. Its placement predates divergence of Nymphaeales water lilies and Austrobaileyales including star anise. Traits like vesselless wood, single aperturate pollen, spirally arranged ascidiate carpels reflect ancestral states useful for reconstructing protoflower ancestral morphology. Magnolia, Nymphaea, Illicium diverge later within mesangiosperms, not basal, making Amborella model organism genome project.

Ref: APG IV 2016, Botanical Journal Linnean Society, Amborella sister to all angiosperms

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