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Apostasioideae

Cladus: Eukaryota
Regnum: Plantae
Divisio: Magnoliophyta
Classis: Liliopsida
Subclassis: Liliidae
Ordo: Asparagales
Familia: Orchidaceae
Subfamilia: Apostasioideae
Genera: Apostasia - Neuwiedia

Name

Apostasioideae Horan. (1847)

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The subfamily Apostasioideae belongs to the orchid family (Orchidaceae).

It is a clade, but there is bootstrap support that it is a sister to the other orchid subfamilies. A bootstrap is a method for evaluating the statistical importance of positions of different branches in a phylogenetic tree (= a treelike structure giving the evolutionary development of organisms).

The apostasioid orchids are the most primitive orchids, with only two genera. Neuwiedia has 3 fertile, abaxial (= facing away from the stem) anthers, while Apostasia has two fertile abaxial anthers and a filamentous staminode (= a sterile stamen).

These primitive features make them, according to some authorities , not true orchids but rather ancestors of modern orchids. However, modern studies (Stern, Cheadle and Thorsch, 1993) point out that the apostasioid orchids are uniquely defined ( = autapomorphous). This makes them unsuitable as models to be the ancestors of the orchids.

References

* Stern, W. L., V. Cheadle, and J. Thorsch (1993). "Apostasiads, systematic anatomy, and the origins of Orchidaceae". Botanical Journal of the Linnean Society 111: 411–445. doi:10.1111/j.1095-8339.1993.tb01913.x.
* A. Kocyan, Y.-L. Qiu, P. K. Endress, and E. Conti (August 2004). "A phylogenetic analysis of Apostasioideae (Orchidaceae) based on ITS, trnL-F and matK sequences". Plant Syst. Evol. 247 (3/4): 203–213. doi:10.1007/s00606-004-0133-3. online pdf.format
* Pridgeon, A.M.; Cribb, P.J.; Chase, M.W. & F. N. Rasmussen (1999): Genera Orchidacearum Vol.1, Oxford U. Press. ISBN 0-19-850513-2

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Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License