Cornaceae

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Cornaceae
Cornus suecica Ume River.jpg
Cornus suecica
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Cornales
Family: Cornaceae
Genera

 Alangium
 Cornus

Cornaceae is a cosmopolitan family of flowering plants in the order Cornales. It contains approximately 85 species in two genera,[1] Alangium and Cornus. They are mostly trees and shrubs, which may be deciduous or evergreen, although a few species are perennial herbs. Members of the family usually have opposite or alternate simple leaves, four- or five-parted flowers clustered in inflorescences or pseudanthia, and drupaceous fruits.[2] In northern temperate areas, Cornaceae are well known from the dogwoods Cornus.

The systematics of Cornaceae has been remarkably unsettled and controversial, and many genera have been added to it and removed from it over time. (One researcher called it a "dustbin."[3]) Molecular phylogenetics have clarified the relatedness of some associated genera, and at least nine genera that were previously included in Cornaceae have been eliminated from the order Cornales entirely,[4] but the circumscription of Cornaceae is still unclear. The Angiosperm Phylogeny Group usually defines Cornaceae as comprising the genera Cornus and Alangium as well as five genera now separated into the family Nyssaceae. However, many of these genera are sometimes split off into their own families (e.g. Alangiaceae), and the usage remains inconsistent.[4][5]

Fossil record[edit]

The oldest fossil that can be related to Cornaceae is †Hironoia fusiformis, an extict taxon collected from the Futaba Group sediments at Kamitikaba, Japan. Synapomorphies of the fruits of the fossil occur also in extant Cornaceae. The age of the sediments is of early Coniacian to early Santonian (about 88 Ma).[6] Although the mosaic of characters in Hironoia precludes assignment to an extant genus, the fiber rather than sclereid composition of the fruit places it within the Nyssaceae-Mastixiaceae. Other possible Cornaceae from Cretaceous sediments include endocarps resembling Cornus from the Santonian-Campanian mesofossil assemblage of Åsen. In slightly younger Late Cretaceous sediments (Maastrichtian) four genera of fossil mastixioid fruits (Beckettia, Eomastixia, Mastixicarpum and Mastixiopsis) have been described from Germany.[7]

References[edit]

Cornus sanguineus with ladybird.jpg
  1. ^ Christenhusz, M. J. M. & Byng, J. W. (2016). "The number of known plants species in the world and its annual increase". Phytotaxa. Magnolia Press. 261 (3): 201–217. doi:10.11646/phytotaxa.261.3.1. 
  2. ^ Kubitzki, K. (2004). Cornaceae. In The Families and Genera of Vascular Plants Volume 6: Flowering Plants: Dicotyledons: Celastrales, Oxidales, Rosales, Cornales, Ericales (Kubitzki, ed.). Springer-Verlag, New York.
  3. ^ Eyde, R. H. (1988). Comprehending Cornus - puzzles and progress in the systematics of the dogwoods. Botanical Review 54, 233-351.
  4. ^ a b Fan, C. Z., and Xiang, Q. Y. (2003). Phylogenetic analyses of Cornales based on 26S rRNA and combined 26S rDNA-matK-rbcL sequence data. American Journal of Botany 90, 1357-1372.
  5. ^ Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society. 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-06-26. 
  6. ^ The Timetree of Life edited by S. Blair Hedges and Sudhir Kumar, OUP Oxford, 23. apr. 2009 - 576 pages, ISBN 0191560154, 9780191560156.
  7. ^ Hironoia fusiformis gen. et sp. nov.; a cornalean fruit from the Kamikitaba locality (Upper Cretaceous, Lower Coniacian) in northeastern Japan by Masamichi Takahashi,Peter R. Crane and Steven R Manchester, Article · January 2003, DOI: 10.1007/s10265-002-0062-6 · Source: PubMed.

External links[edit]