Geraniales

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Geraniales
Geranium palustre
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Clade:
Malvids
Order: Geraniales
Juss. ex Bercht. & J.Presl[1]
Families

Geraniales is a small

trees
.

Flower morphology of the Geraniales is rather conserved. They are usually perfectly pentamerous and pentacyclic without fused organs besides the carpels of the superior gynoecium. The androecium is obdiplostemonous. Only a few genera are tetramerous (Francoa, Tetilla, Melianthus). In some genera some stamens (Pelargonium) or a complete whorl of stamens are reduced (Erodium, Melianthus). In the genera Hypseocharis and Monsonia there are 15 instead of the usual ten stamens. Most genera bear nectariferous flowers.[2] The nectary glands are formed by the receptacle and are localised at the bases of the antesepalous stamens.[2][3]

The economic importance of Geraniales is low. Some species of the genus

Paleobotanic
record is missing.

Taxonomy

Origins

The

O Prirozenosti Rostlin, by Friedrich von Berchtold and Jan Svatopluk Presl, hence ex Bercht. & J.Presl.[7] However, Berchtold and Presl also only described a rad (ordo) of five genera, which they called Geraniae.[8] Other authorities have given the authority to Dumortier who described the family Geraniaceae, consisting of two tribes, Pelargonieae and Geranieae, each with three genera.[9]

Circumscription

Geraniales contains two

genera and about 830 species.[10] For a historical account of the circumscription of the order, see Price and Palmer (1993) Table 1.[11]

Under the Cronquist system (1988),[12] the Geraniales comprised the following five families:

While the

Rutiflorae:[13]

Other modern

subfamilies
of Geraniaceae.

Molecular phylogenetics: Angiosperm Phylogeny Group

The elucidation of the relationships within the order by

rosid subclade
.

The family circumscription of the Angiosperm Phylogeny Group (APG) of 1998 placed Geraniales Dumort. amongst the rosids with the following six families:[15]

Geraniales

Dumort. 1829[16]

  • A.Juss.
    , 1832
  • Geraniaceae
    Wedd.
    , 1861]
  • Hutch.
    , 1926
  • Meyen
    , 1834
  • J.Presl
    , 1820
  • Klotzsch
    , 1836

Hypseocharitaceae were a small family of eight species of the genus Hypseocharis found in the tropical mountainous regions of the Andes.[17] The APG provided the option of considering them as a separate family or subsumed into Geraniaceae. By 2003, when the APG was published, it was apparent that the small families Francoaceae, Greyiaceae and Melianthaceae were closely related and were collapsed into one family as Melanthiaceae with Francoaceae as an optional synonym. Thus the number of families was reduced to four.[18]

The

Melianthaceae, and Ledocarpaceae was included within the Vivianiaceae.[1]

However, Considerable rearrangements took place in the 2016

Melianthaceae
, due to
sensu stricto
(s.s.), Melianthaceae (Bersama Fresen. and Melianthus L.) and Ledocarpaceae. Here, Vivianiaceae is used as a later synonym for Ledocarpaceae. This due to conflicting evidence (see Palazzesi et al., 2012). The APG chose to follow the broader circumscription for the time being till these differences are resolved.

This leaves the order Geraniales with only two families:

Melianthaceae, Rhynchothecaceae and Vivianiaceae).[19]

The Vivianiaceae and Ledocarpaceae were included within the Geraniaceae, and the Hypseocharitaceae within the Oxalidaceae, which are now treated in the order Oxalidales. The Melianthaceae were placed within the Sapindales, the Greyiaceae and Francoaceae within the Rosales, the latter subsumed within the Saxifragaceae.

Recent comparison of DNA-fragments from species within the order resulted in the following phylogenetic tree.[20]

Geraniales
Francoaceae in sensu lato:

Melianthaceae

Notes

  1. seed plants (Ann. Missouri Bot. Gard. 1993
    )

References

  1. ^ a b APG III 2009.
  2. ^
    PMID 28025289
    .
  3. PMID 28961907
    .
  4. ^ Jussieu 1789, Ordo XIII Gerainia, Les Geraines p. 268
  5. ^ ICN 2012, 18.2 Names of families and subfamilies, tribes and subtribes.
  6. ^ Candolle 1813, Des familles et des tribus pp. 192–195
  7. ^ Tropicos 2015, Geraniales Juss. ex Bercht. & J. Presl
  8. ^ Berchtold & Presl 1820, Geraniae p. 221
  9. ^ Dumortier 1829, Geraniaceae Juss. p. 46
  10. ^ Christenhusz & Byng 2016.
  11. ^ a b c Price & Palmer 1993.
  12. ^ Cronquist 1988.
  13. ^ Dahlgren 1980.
  14. ^ Chase et al 1993.
  15. ^ APG I 1998.
  16. ^ Dumortier 1829.
  17. ^ Watson & Dallwitz 2016, Hypseocharitaceae Weddell
  18. ^ APG II 2003.
  19. ^ APG IV 2016.
  20. doi:10.7287/peerj.preprints.3127v1
    . Retrieved 2017-09-27.

Bibliography

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