Asteridae

(botany) A large subclass of dicotyledonous plants in the class Magnoliopsida; plants are sympetalous, with unitegmic, tenuinucellate ovules and with the stamens usually as many as, or fewer than, the corolla lobes and alternate with them.

A large subclass of the class Magnoliopsida (dicotyledons) of the division Magnoliophyta (Angiospermae), the flowering plants, consisting of 11 orders, 49 families, and more than 60,000 species. The Asteridae are mostly sympetalous with unitegmic, tenuinucellate ovules and with the stamens usually as many as, or fewer than, the corolla lobes and alternate with them. Most of them have two carpels, but a few have as many as five or even more carpels, and a few others are pseudomonomerous. The largest orders of the group are the Asterales (about 20,000 species), Scrophulariales (about 11,000 species), Lamiales (about 7800 species), and Rubiales (about 6500 species). Other orders are the Gentianales, Plantaginales, Solanales, Callitrichales, Campanulales, Calycerales, and Dipsacales. See individual articles on each order. See also Magnoliophyta; Magnoliopsida; Plant kingdom.

The noun has one meaning:

Meaning #1: a group of mostly sympetalous herbs and some trees and shrubs mostly with 2 fused carpels; contains 43 families including Campanulales; Solanaceae; Scrophulariaceae; Labiatae; Verbenaceae; Rubiaceae; Compositae; sometimes classified as a superorder
  Synonym: subclass Asteridae

Asteridae is a botanical name at the rank of subclass. Circumscription of the subclass has varied with the taxonomic system being used but by definition always includes the family Asteraceae (Compositae). One of the better-known and more influential systems that formally recognized subclass Asteridae was the Cronquist system devised by botanist Arthur Cronquist, which included the orders:

Campanula portenschlagiana (Campanulaceae)

• Gentianales
• Solanales
• Lamiales
• Callitrichales
• Plantaginales
• Scrophulariales
• Campanulales
• Rubiales
• Dipsacales
• Calycerales
• Asterales

Most of the above orders as defined by Cronquist have been dramatically redefined on the basis of recent molecular systematic studies.

To a large extent Cronquist's subclass Asteridae corresponds with the older concepts of Sympetalae and Tubiflorae, groups that were defined by having their petals united into a tube. However, these older classifications contained some sympetalous families, such as Cucurbitaceae, that are now known not to be closely related. Cronquist's concept also corresponds closely with the APG II group of euasterids but the APG does not formally recognize a group called "Asteridae" (or any other group above the rank of order).

Recent phylogenetic studies have suggested that several families, including three major orders not included in Asteridae by Cronquist, Ericales, Cornales, and Apiales, also belong to the asterid group. The circumscription of subclass Asteridae, as well as the circumscriptions of the orders contained within it, is currently in a state of flux; many systematic botanists refer to these as clades (asterids, euasterids, etc., rather than use formal names such as subclass Asteridae.

External links

• Asteridae (Cronquist system)
• Asterids
• Phylogeny and the evolution of flower symmetry in the Asteridae
• The Phylogeny of the Asteridae sensu lato Based on Chloroplast ndhF Gene Sequences (link to abstract)
• Phylogeny of the Asteridae s. str. based on rbcL sequences, with particular reference to the Dipsacales (link to abstract)bat-smg:Astražėidē

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