Hydrostachys

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Hydrostachys
Hydrostachys imbricata.jpg
Hydrostachys imbricata
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Cornales
Family: Hydrostachyaceae
Engl. [1]
Genus: Hydrostachys
Thouars
Species

Approximately 22; see text.

Hydrostachys is a genus of about 22 species [2] of flowering plants native to Madagascar and southern and central Africa. It is the only genus in the family Hydrostachyaceae. All species of Hydrostachys are aquatic, growing on rocks in fast-moving water. They have tuberous roots, usually pinnately compound leaves, and highly reduced flowers on dense spikes. [3]

Contents

Phylogenetic placement of Hydrostachys is particularly problematic. Due to its specialized aquatic morphology, it has often been grouped with other aquatic plants, such as the family Podostemaceae. However, embryological, floral, and other morphological characters do not support this placement, and molecular data suggest that Hydrostachys is related to taxa in the order Cornales. [3] [4] Its position in Cornales is uncertain; it may be basal to the rest of the order, or fall within the family Hydrangeaceae. [3] [5] [6] It shares few morphological similarities with other Cornales. [3]

Species

(This list may be incomplete.)

Related Research Articles

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<span class="mw-page-title-main">Cornales</span> Order of flowering plants

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<i>Myrothamnus</i> Genus of shrubs

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<span class="mw-page-title-main">Huaceae</span> Family of flowering plants

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<span class="mw-page-title-main">Centroplacaceae</span> Family of flowering plants

Centroplacaceae is a family of flowering plants in the order Malpighiales and is recognized by the APG III system of classification. The family comprises two genera: Bhesa, which was formerly recognized in the Celastraceae, and Centroplacus, which was formerly recognized in the Euphorbiaceae, together comprising six species. The Angiosperm Phylogeny Group determined that based on previous phylogenetic analysis, these two genera formed an isolated clade and recognition of the family was "reasonable."

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References

  1. 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 2013-07-06.
  2. Christenhusz, M. J. M.; Byng, J. W. (2016). "The number of known plants species in the world and its annual increase". Phytotaxa. 261 (3): 201–217. doi: 10.11646/phytotaxa.261.3.1 .
  3. 1 2 3 4 Albach, D. C., Soltis, D. E., Chase, M. W., and Soltis, P. S. (2001). Phylogenetic placement of the enigmatic angiosperm Hydrostachys. Taxon 50, 781-805.
  4. Angiosperm Phylogeny Group (2016). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV". Botanical Journal of the Linnean Society . 181 (1): 1–20. doi: 10.1111/boj.12385 . ISSN   0024-4074.
  5. 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 Botany90, 1357-1372.
  6. 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.