ANA & C grade

• Basal angiosperms

  • 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) 

    • Austrobaileyales (woody aromatic plants including star anise)

  • ANITA stands for Amborella, Nymphaeales, I lliciales, Trimeniaceae, and Austrobaileya

  • 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

  • The exact relationships between Amborella, Nymphaeales and Austrobaileyales are not yet clear

    • Although most studies show that Amborella and 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 is sister to the rest of the angiosperms, and one in which a clade of Amborella and Nymphaeales is in this position

    • A 2014 paper says that it presents "the most convincing evidence to date that Amborella plus Nymphaeales together represent the earliest diverging lineage of extant angiosperms"

    • A number of other studies identify Amborella the most basal of all angiosperms

1.  Amborellales

Woody; vessels lacking dioecious; flw T5–8, A∞, G5–8, ovule 1/carpel, embryo sac 9-nucleate 1 species, New Caledonia

• Austrobaileya is the sole genus consisting of a single species that constitutes the entire flowering plant family Austrobaileyaceae. The species Austrobaileya scandens grows naturally only in the Wet Tropics rainforests of northeastern Queensland, Australia.

• The name A. maculata is recognized as a synonym of A. scandens.

• Austrobaileya plants grow as woody lianas or vines. Their main growing stems loosely twine, with straight, extending, leafy branches. The leaves are leathery, veined and simple. The leaves produce essential oils in spherical ethereal oil cells. Their foliage is damaged by oxidation in direct sunlight, so it tends to grow beneath the rainforest canopy, in low-sunlight and very humid conditions.[10] Like many other flowering plants growing in the understory of tropical rainforest, it does not have palisade mesophyll tissue or low leaf photosynthetic rates. It relies strongly on vegetative reproduction for continuation of the species.

•  2. Nymphaeales

• Herbaceous, aquatic; cambium absent; aerenchyma; flw T4–12, A1–∞, embryo sac 4-nucleate seeds operculate, perisperm mucilage; alkaloids (no benzylisoquinolines)

• The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae(water lilies). It is one of the three orders of basal angiosperms, an early-diverginggrade of flowering plants. At least 10 morphological characters unite the Nymphaeales. Molecular synapomorphies are also known.

• The Plant List, created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden recognizes about 70 species in 11 genera within the order,[3] but a phylogenetic study of the genus Nymphaea implies that the number of species could be more than 90.[4] The difference in species numbers is due almost entirely to the difficulty of delineating species in the genus Nymphaea.

• All of the species are rhizomatous aquatic herbs with a broad leaf base and large, showy flowers.

• Cabombaceae

  • The Cabombaceae are a family of aquatic, herbaceous flowering plants. A common name for its species is water shield.[3] The family is recognised as distinct in the Angiosperm Phylogeny Group IV system (2016). The family consists of two genera of aquatic plants, Brasenia and Cabomba, totalling six species.[4]

  • The Cabombaceae are all aquatic, living in still or slow-moving waters of temperate and tropical North and South America, Europe, Asia, Africa, and Australia. Although found on all continents but Antarctica, the plants tend to grow in relatively restricted ranges

• Hydatellaceae 

  • Hydatellaceae are a family of small, aquatic flowering plants. The family consists of tiny, relatively simple, plants occurring in Australasia and India

• Nymphaeaceae

  • Commonly called water lilies

  • They live as rhizomatous aquatic herbs in temperate and tropical climates around the world

  • The family contains five genera with about 70 known species

  • Water lilies are rooted in soil in bodies of water, with leaves and flowers floating on or emergent from the surface

  • Leaves are round, with a radial notch in Nymphaea and Nuphar, but fully circular in Victoria and Euryale

  • The flowers of extant water lilies with the most floral parts are more derived than the genera with fewer floral parts

  • Genera with more floral parts, Nuphar, Nymphaea

  • Victoria, have a beetle pollination syndrome, while genera with fewer parts are pollinated by flies or bees, or are self- or wind-pollinated

  • Thus, the large number of relatively unspecialized floral organs in the Nymphaeaceae is not an ancestral condition for the clade

3 .  Austrobaileyales

Woody, vessels solitary flw T>10, A∞, G ca.9, embryo sac 4-nucleate tiglic acid, aromatic terpenoids

Only one species endemic to Australia

 4.  Chloranthales

Woody; foliar sclereids K and C distinct aromatic terpenoids

• The only family in the order Chloranthales

• It is not closely related to any other family of flowering plants, and is among the early-diverging lineages in the angiosperms

• They are woody or weakly woody plants occurring in Southeast Asia, the Pacific, Madagascar, Central and South America, and the West Indies

• The family consists of four extant genera, totalling about 77 known species. Some species are used in traditional medicine

• The type genus is Chloranthus

• The fossil record of the family, mostly represented by pollen such as Clavatipollenites, extends back to the dawn of the history of flowering plants in the Early Cretaceous, and have been found on all continents

• Older terms

• Paleodicots (sometimes spelled "palaeodicots") is an informal name used by botanists (Spichiger & Savolainen 1997, Leitch et al. 1998) 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 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 (not included among the "paleodicots" by Leitch et al. 1998), Chloranthaceae, and the magnoliid clade (orders Canellales, Piperales, Laurales, and Magnoliales).[12] Subsequent research has added Hydatellaceae to the paleodicots

• The term paleoherb is another older term for flowering plants which are neither eudicots nor monocots