Gunnerales

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. DNA analysis proved definitive, but the grouping of the two families was a surprise, given their very dissimilar morphologies. In the older systems of Cronquist (1981, 1988) and Takhtajan (1997), the Gunneraceae were in the Rosidae, and the Myrothamnaceae were in the Hamamelids. In modern classification systems, such as APG III and APG IV, this order was the first to diverge from the core eudicots. 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.