Gunnerales

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Order of flowering plants

title: "Gunnerales" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["gunnerales", "angiosperm-orders", "dioecious-plants"] description: "Order of flowering plants" topic_path: "general/gunnerales" source: "https://en.wikipedia.org/wiki/Gunnerales" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Order of flowering plants ::

| fossil_range = Aptian - present, |image = Gunnera tinctoria0.jpg |image_caption = Gunnera |taxon = Gunnerales |authority = Takht. ex Reveal |subdivision_ranks = Families |subdivision = *Gunneraceae

The Gunnerales are an order of flowering plants. In the APG III (2009) and APG IV systems (2016), the order contains two genera: Gunnera (family Gunneraceae) and Myrothamnus (Myrothamnaceae). In the Cronquist system (1981), the Gunneraceae were in the Haloragales and Myrothamnaceae in the Hamamelidales. Some of the oldest fossils come from fossils dating the Aptian stage in places like Antarctica, Egypt and Argentina with these early pollen samples being known as Tricolpites. At that time those landmasses were part of the continent known as Gondwana.

Description

Both families contain ellagic acid. Phloem cells contain a large number of plastids and the leaves have dented borders.

The plants are dioecious and possess small flowers without perianth, and the stigma is, at least weakly, secretory. Gunnerales characters shared with the core eudicots are cyanogenesis via phenylalanine, metabolic pathways of isoleucine or valine, presence of the DNA sequence of PI-dB motif, and is common to have a small deletion in the sequence of 18S ribosomal DNA. The characters which it shares with the core eudicots, and also with Buxales and Trochodendrales, are an absence of benzylisoquinoline alkaloids, euAP3 + TM6 genes (gene duplication paleoAP3: Class B), and a loss of the mitochondrial gene rps2.

Ecology

Despite being related, the Myrothamnaceae and the Gunneraceae look very different:

  • The Gunneraceae are a mesophilic herb (often oversized), and the hydathodes are well developed and secrete mucilage or perhaps a resinous coating.
  • The Myrothamnaceae are a reviviscent shrub of arid habitats, and the hydathodes are poorly developed and secrete plant resin. Both have flowers without perianth, but the details of pollen (e.g. Zavada and Dilcher see 1986 10, Wanntorp et al. 2004th 2004b 11 and 12) differ. In Wilkinson 2000 13 is a table of differences.

References

References

  1. (1996). "Aptian-Turonian palynology of the Ghazalat-1 Well (GTX-1), Qattara Depression, Egypt". Review of Palaeobotany and Palynology.
  2. Angiosperm Phylogeny Group. (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society.
  3. 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]].
  4. (December 2012). "Evolution of the Austral-Antarctic flora during the Cretaceous: New insights from a paleobiogeographic perspective". Revista chilena de historia natural.
  5. (April 2012). "Palynostratigraphic study of the Early Cretaceous Río Mayer and Kachaike formations at the Quebrada El Moro Section, Austral Basin, southwestern Argentina". Cretaceous Research.
  6. (2023-07-01). "Maastrichtian palynological assemblages from the Chorrillo Formation, Patagonia, Argentina". Review of Palaeobotany and Palynology.

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gunneralesangiosperm-ordersdioecious-plants