Cornales is an order of flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s, basal among the asterids

Asterids

In the APG II system for the classification of flowering plants, the name asterids refers to a clade .Most of the taxa belonging to this clade had been referred to the Asteridae in the Cronquist system and to the Sympetalae in earlier systems...

, containing about 600 species. Plants within Cornales usually have four-parted flowers, drupaceous

Drupe

In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...

 fruits, and inferior gynoecia

Gynoecium

Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...

 topped with disc-shaped nectaries. Under the APG

Angiosperm Phylogeny Group

The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants that would reflect new knowledge about plant relationships discovered through phylogenetic studies., three...

 system, Cornales includes the following families:

• Cornaceae
  Cornaceae
  Cornaceae is a cosmopolitan family of flowering plants in the order Cornales. It contains approximately 110 species, mostly trees and shrubs, which may be deciduous or evergreen. Members of this family usually have opposite or alternate simple leaves, four- or five-parted flowers clustered in...
  
   (the dogwood
  Dogwood
  The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
  
   family, including Nyssaceae
  Nyssaceae
  Nyssaceae is a small family of flowering trees closely related to and often included within the dogwood family . Nyssaceae commonly includes the following genera:...
  
  , the tupelo
  Tupelo
  The tupelo , black gum, or pepperidge tree, genus Nyssa , is a small genus of about 9 to 11 species of trees with alternate, simple leaves...
  
  s)
• Curtisiaceae (cape lancewood)
• Grubbiaceae
  Grubbiaceae
  Grubbiaceae is a family of flowering plants endemic to the Cape floristic region of South Africa. The family includes five species of leathery-leaved shrubs in two genera, Grubbia and Strobilocarpus. They are commonly known as sillyberry....
  
   (the sillyberry family)
• Hydrangeaceae
  Hydrangeaceae
  Hydrangeaceae are a family of flowering plants in the order Cornales, with a wide distribution in Asia and North America, and locally in southeastern Europe.-Overview:...
  
   (the hydrangea
  Hydrangea
  Hydrangea is a genus of about 70 to 75 species of flowering plants native to southern and eastern Asia and North and South America. By far the greatest species diversity is in eastern Asia, notably China, Japan, and Korea...
  
   family)
• Hydrostachyaceae
• Loasaceae
  Loasaceae
  The Loasaceae is a family of 15-20 genera and about 200-260 species of flowering plants in the order Cornales, native to the Americas and Africa. The family comprises annual, biennial and perennial herbaceous plants, and a few shrubs and small trees.Genera...
  
   (the stickleaf family)

Phylogeny

Cornales is sister to the remainder of the large and diverse asterid clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

.

Members of Cornales are highly geographically disjunct

Disjunct distribution

In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...

 and morphologically

Morphology (biology)

In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 diverse, which has led to considerable confusion regarding the proper circumscription of the groups within the order and the relationships between them. Under the Cronquist system

Cronquist system

The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in his texts An Integrated System of Classification of Flowering Plants and The Evolution and Classification of Flowering Plants .Cronquist's system places flowering plants into two...

 the order comprised the families Cornaceae, Nyssaceae, Garryaceae

Garryaceae

Garryaceae is a small family of dicotyledons, including only two genera:*Garrya Douglas ex Lindl., 1834. About 16-18 species.*Aucuba Thunb., 1783. About 3-10 species....

, and Alangiaceae

Alangiaceae

Alangiaceae is a small family of small dicotyledon trees, shrubs or lianas, closely related to the Cornaceae .There is only one genus, Alangium, with seventeen species....

, and was placed among the Rosidae

Rosidae

Under the International Code of Botanical Nomenclature , Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being that it includes the family Rosaceae....

, but this interpretation is no longer followed. Many families and genera previously associated with Cornales have been removed, including Garryaceae, Griselinia

Griselinia

Griselinia is a genus of seven species of shrubs and trees, with a highly disjunct distribution native to New Zealand and South America. It is a classic example of the Antarctic flora....

, Corokia

Corokia

Corokia is a genus in the Argophyllaceae family comprising about ten species native to New Zealand and one native to Australia. Corokia species are shrubs or small trees with zigzagging branches. In fact, Corokia cotoneaster is commonly known as wire-netting bush. The stems of the shrubs are dark...

, and Kaliphora

Kaliphora

Kaliphora madagascarensis is a species of evergreen shrub or small tree. It is endemic to Madagascar, where it inhabits subhumid woodlands and forests in eastern Madagascar, in the provinces of Antananarivo, Antsiranana, Fianarantsoa, and Mahajanga....

, among others.

Molecular data suggest that there are four clades within the Cornales: Cornus-Alangium

Alangium

Alangium is a small genus of flowering plants. The genus is included either in a broad view of the dogwood family Cornaceae, or as the sole member of its own family Alangiaceae. Alangium has about 24 species, but some of the species boundaries are not entirely clear...

, nyssoids-mastixioids

Nyssaceae

Nyssaceae is a small family of flowering trees closely related to and often included within the dogwood family . Nyssaceae commonly includes the following genera:...

, Hydrangeaceae-Loasaceae, and Grubbia

Grubbiaceae

Grubbiaceae is a family of flowering plants endemic to the Cape floristic region of South Africa. The family includes five species of leathery-leaved shrubs in two genera, Grubbia and Strobilocarpus. They are commonly known as sillyberry....

-Curtisia

Curtisia

Curtisia dentata is a flowering tree from Southern Africa...

, with Hydrostachyaceae in an uncertain position, possibly basal. However, the relationship between these clades is unclear, and as a result of many historical taxonomic interpretations and differing opinions regarding the significance of morphological variations, rankings of taxa within the order are inconsistent. These difficulties in interpreting the systematics of Cornales may represent an early and rapid diversification of the groups within the order.