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, I lliciales, 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.
Amborella , Nymphaeales and Austrobaileyales, in that order, are basal to all other angiosperms. [3]
Angiospermae | |
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 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). [6] Subsequent research has added Hydatellaceae to the paleodicots. [7]
The term paleoherb is another older term for flowering plants which are neither eudicots nor monocots. [8]
Asparagales is an order of plants in modern classification systems such as the Angiosperm Phylogeny Group (APG) and the Angiosperm Phylogeny Web. The order takes its name from the type family Asparagaceae and is placed in the monocots amongst the lilioid monocots. The order has only recently been recognized in classification systems. It was first put forward by Huber in 1977 and later taken up in the Dahlgren system of 1985 and then the APG in 1998, 2003 and 2009. Before this, many of its families were assigned to the old order Liliales, a very large order containing almost all monocots with colorful tepals and lacking starch in their endosperm. DNA sequence analysis indicated that many of the taxa previously included in Liliales should actually be redistributed over three orders, Liliales, Asparagales, and Dioscoreales. The boundaries of the Asparagales and of its families have undergone a series of changes in recent years; future research may lead to further changes and ultimately greater stability. In the APG circumscription, Asparagales is the largest order of monocots with 14 families, 1,122 genera, and about 36,000 species.
Liliales is an order of monocotyledonous flowering plants in the Angiosperm Phylogeny Group and Angiosperm Phylogeny Web system, within the lilioid monocots. This order of necessity includes the family Liliaceae. The APG III system (2009) places this order in the monocot clade. In APG III, the family Luzuriagaceae is combined with the family Alstroemeriaceae and the family Petermanniaceae is recognized. Both the order Lililiales and the family Liliaceae have had a widely disputed history, with the circumscription varying greatly from one taxonomist to another. Previous members of this order, which at one stage included most monocots with conspicuous tepals and lacking starch in the endosperm are now distributed over three orders, Liliales, Dioscoreales and Asparagales, using predominantly molecular phylogenetics. The newly delimited Liliales is monophyletic, with ten families. Well known plants from the order include Lilium (lily), tulip, the North American wildflower Trillium, and greenbrier.
The Laurales are an order of flowering plants. They are magnoliids, related to the Magnoliales.
The Magnoliales are an order of flowering plants.
The dicotyledons, also known as dicots, are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, that the seed has two embryonic leaves or cotyledons. There are around 200,000 species within this group. The other group of flowering plants were called monocotyledons, typically each having one cotyledon. Historically, these two groups formed the two divisions of the flowering plants.
The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. One of the traits is the absence of a vascular cambium, which is required to produce both xylem (wood) and phloem, which therefore are missing. Molecular synapomorphies are also known.
Monocotyledons, commonly referred to as monocots, are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided; the rest of the flowering plants have two cotyledons and were classified as dicotyledons, or dicots.
Austrobaileyales is an order of flowering plants consisting of about 100 species of woody plants growing as trees, shrubs and lianas. The best-known species is Illicium verum, commonly known as star anise. The order belongs to the group of basal angiosperms, the ANA grade, which diverged earlier from the remaining flowering plants. Austrobaileyales is sister to all remaining extant angiosperms outside the ANA grade.
Amborella is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellales and contains a single species, Amborella trichopoda. Amborella is of great interest to plant systematists because molecular phylogenetic analyses consistently place it as the sister group to all other flowering plants, meaning it was the earliest group to evolve separately from all other flowering plants.
The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships discovered through phylogenetic studies.
Nelumbonaceae is a family of aquatic flowering plants. Nelumbo is the sole extant genus, containing Nelumbo lutea, native to North America, and Nelumbo nucifera, widespread in Asia. At least five other genera, Nelumbites, Exnelumbites, Paleonelumbo, Nelumbago, and Notocyamus are known from fossils.
The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants (angiosperms) which are mainly characterized by having two seed leaves (cotyledons) upon germination. The term derives from dicotyledon. Previously, they were called tricolpates or non-magnoliid dicots by past authors. The current botanical terms were introduced in 1991, by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton, to emphasize the later evolutionary divergence of tricolpate dicots from earlier, less specialized, dicots.
Schisandraceae is a family of flowering plants with 3 known genera and a total of 92 known species. Such a family has been recognized by most taxonomists, at least for the past several decades. Before that, the plants concerned were assigned to family Magnoliaceae and Illiciaceae.
Chloranthaceae is a family of flowering plants (angiosperms), 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 according to Christenhusz and Byng in 2016. 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 has been found on all continents.
Trimeniaceae is a family of flowering plants recognized by most taxonomists, at least for the past several decades. It is a small family of one genus, Trimenia, with eight known species of woody plants, bearing essential oils. The family is subtropical to tropical and found in Southeast Asia, eastern Australia and on several Pacific Islands.
The APG II system of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Group. It was a revision of the first APG system, published in 1998, and was superseded in 2009 by a further revision, the APG III system.
Magnoliids, Magnoliidae or Magnolianae are a clade of flowering plants. With more than 10,000 species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others, it is the third-largest group of angiosperms after the eudicots and monocots. The group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves.
Mesangiospermae is a clade of flowering plants (angiosperms), informally called "mesangiosperms". They are one of two main groups of angiosperms. It is a name created under the rules of the PhyloCode system of phylogenetic nomenclature. There are about 350,000 species of mesangiosperms. The mesangiosperms contain about 99.95% of the flowering plants, assuming that there are about 175 species not in this group and about 350,000 that are. While such a clade with a similar circumscription exists in the APG III system, it was not given a name.
In phylogenetic nomenclature, the Pentapetalae are a large group of eudicots that were informally referred to as the "core eudicots" in some papers on angiosperm phylogenetics. They comprise an extremely large and diverse group accounting for about 65% of the species richness of the angiosperms, with wide variability in habit, morphology, chemistry, geographic distribution, and other attributes. Classical systematics, based solely on morphological information, was not able to recognize this group. In fact, the circumscription of the Pentapetalae as a clade is based on strong evidence obtained from DNA molecular analysis data.