Dilleniaceae

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Dilleniaceae
Temporal range: Early Paleogene – Recent (but see text) 52–0Ma
Hibbertia stellaris.jpg
Hibbertia stellaris
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Core eudicots
Order: (unplaced)
Family: Dilleniaceae
Salisb.[1]
Genera

APG II system recognizes the following genera:

Dilleniaceae is a family of flowering plants. Such a family has been universally recognized by taxonomists. It is known to gardeners for the genus Hibbertia, which contains many commercially valuable garden species.

Description and Distribution[edit]

The family consists of about a dozen genera, of a few hundred species, found in the tropics and sub-tropics plus entire Australia. Most of the members in it are woody plants - lianas or trees such as Dillenia - but herbaceous species such as Pachynema are also present in Dilleniaceae. The leaves of the plants in the family are wide and well-developed; however in Pachynema and certain species of Hibbertia they are heavily modified. The flowers are mainly showy and colorful with visible reproductive components. Buzz pollination is common in the group.[2] Fruits of some species as Dillenia indica (elephant apple) are edible.

Taxonomy and Phylogeny[edit]

The position of the family in the phylogenetic tree and its classification among the other eudicots is uncertain.[3] Some studies suggested that Dilleniaceae may be sister to Rhabdodendraceae which is a clade that was thought to be sister to all the rest Caryophyllales. The caryophyllid Rhabdodendron and the members in the family with the questionable placement in fact share some morphological characteristics but it was found that Rhabdodendraceae is actually sister only to the core members of its order.

Another possible situation places Dilleniaceae as an ancient group, sister to the superrosidae clade (the family shares some common morphology with Vitales) but this is not absolutely proven.

The APG II system, of 2003 (unchanged from the APG system, of 1998), also recognizes this family, unplaced as to order, assigned to the clade core eudicots.

APG II debates either including it in order Caryophyllales or reinstating the order Dilleniales for just this one family, but decides to leave it unplaced.

Evolution[edit]

All in all, the family is remarkable because of its variability of morphological characteristics that now are much steadier in other Angiosperm groups. Thus, Dilleniaceae may be an ancient clade that expresses some phylogenetic relation between the higher Eudicots and the rather more primitive groups.[4] It is estimated that the clade diverged around 115 millions of years ago in Mid Cretaceous but the crown group was formed much later - only 52 millions of years before the present.[5]

References[edit]

External links[edit]