''Gunnera'' is the sole genus of

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are variously native to

Latin America Latin America or * french: Amérique Latine, link=no * ht, Amerik Latin, link=no * pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

Papuasia Papuasia is a Level 2 botanical region defined in the World Geographical Scheme for Recording Plant Distributions (WGSRPD). It lies in the southwestern Pacific Ocean, in the Melanesia ecoregion of Oceania and Tropical Asia. It comprises th ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, insular Southeast Asia,

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...

.Kew World Checklist of Selected Plant Families
/ref> The stalks of many species are edible.

Taxonomy

''Gunnera'' is the only genus in the family Gunneraceae. The

APG II system The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Gr ...

, of 2003, also recognizes this family and assigns it to the order Gunnerales in the clade

core eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots ...

. The family then consisted of one or two genera, ''Gunnera'' and, optionally, ''

Myrothamnus ''Myrothamnus'' is a genus of flowering plants, consisting of two species of small xerophytic shrubs, in the southern parts of tropical Africa and in Madagascar. ''Myrothamnus'' is recognized as the only genus in the family Myrothamnaceae. Myr ...

'', the latter optionally segregated as a separate family, Myrothamnaceae. This represents a change from the

APG system The APG system (Angiosperm Phylogeny Group system) of plant classification is the first version of a modern, mostly molecular-based, system of plant taxonomy. Published in 1998 by the Angiosperm Phylogeny Group, it was replaced by the improved A ...

, of 1998, which firmly recognized two separate families, unplaced as to order. The

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fu ...

and

APG IV system The APG IV system of flowering plant classification is the fourth version of a modern, mostly molecular-based, system of plant taxonomy for flowering plants (angiosperms) being developed by the Angiosperm Phylogeny Group (APG). It was published ...

recognizes the family Gunneraceae and places ''Myrothamnus'' in Myrothamnaceae; both families are placed in the order Gunnerales in the core eudicots. The genus ''Gunnera'' was named after the Norwegian botanist

Johann Ernst Gunnerus Johan Ernst Gunnerus (26 February 1718 – 25 September 1773) was a Norwegian bishop and botanist. Gunnerus was born at Christiania. He was bishop of the Diocese of Nidaros from 1758 until his death and also a professor of theology at the Unive ...

. At first it was assigned to the family

Haloragaceae Haloragaceae (the watermilfoil family) is a eudicot flowering plant family in the order Saxifragales, based on the phylogenetic APG system. In the Cronquist system, it was included in the order Haloragales. Description The Haloragaceae are ...

, though that presented difficulties that led to the general recognition of the family Gunneraceae, as had been proposed about the beginning of the 20th century. In the meantime, in many publications it had been referred to as being in the Haloragaceae, variously misspelt (as for example "Halorrhagidaceae".) Such references still cause difficulties in consulting earlier works. However, currently ''Gunnera'' is firmly assigned to the

monogeneric In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

family Gunneraceae.

Evolution

''Gunnera'' is thought to be a rather ancient group, with a well-documented fossil history due to the presence of fossilized

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

spores, known by the

palynotaxon Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits ...

'' Tricolpites reticulatus''. It is a

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

n lineage, having originated in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

. The earliest fossilized pollen is known from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

(

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

) of Peru, about 90 million years ago, and within the following 10 million years, ''Gunnera'' had achieved a worldwide distribution, with fossil pollen grains being found in areas where it is not found today, such as western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

, mainland

, and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

. Based on fossil pollen recovered from drilling cores, ''Gunnera'' is also known to have inhabited the now-submerged islands of the Ninetyeast Ridge during the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pala ...

, likely having dispersed there from either

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologic ...

or the then-emergent

Kerguelen Plateau The Kerguelen Plateau (, ), also known as the Kerguelen–Heard Plateau, is an oceanic plateau and a large igneous province (LIP) located on the Antarctic Plate, in the southern Indian Ocean. It is about to the southwest of Australia and is ...

islands. Due to the widespread distribution of ''Gunnera'' during the Cretaceous, it was previously thought that the modern disjunct distribution of the genus was a relic of this period. However, phylogenetic analysis indicates that the majority of ''Gunnera'' species, even those found on entirely different continents, diverged from each other during the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

, indicating that the modern distribution of ''Gunnera'' is a consequence of long-distance dispersal from South America to other parts of the world, rather than relics of a former cosmopolitan distribution. The only species that diverged prior to the Cenozoic is '' Gunnera herteri'' of southeastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, which is thought to be the most ancient species of the genus, its lineage having diverged during the Late Cretaceous, roughly concurrent with the oldest ''Gunnera'' fossil pollen from Peru. The persistence of the ''Gunnera''

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

since the Cretaceous makes it unique among flowering plants, and may have been facilitated by strong niche conservatism, dispersal ability, and being able to aggressively colonize disturbed land.

Description

The 40–50 species vary enormously in

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...

size, with the iconic large-leaved species belonging to the subgenus ''Panke''. The giant rhubarb, or Campos des Loges (''

Gunnera manicata ''Gunnera manicata'', known as Brazilian giant-rhubarb or giant rhubarb, is a species of flowering plant in the family Gunneraceae from the coastal Serra do Mar Mountains of Santa Catarina, Parana and Rio Grande do Sul States, Brazil. It is a ...

''), native to the Serra do Mar mountains of southeastern

, is perhaps the largest species, with

reniform Reniform is an adjective meaning "kidney-shaped" and may specifically refer to: * Reniform leaf, a plant leaf shape * Reniform stigma, a spot on the wings of certain moths * Reniform habit, a type of crystal shape See also * Runiform (disamb ...

or sub-reniform leaves typically long, not including the thick, succulent petiole which may be up to in length. The width of the leaf blade is typically , but on two occasions cultivated specimens (in

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of , ...

, England in 2011 and at Narrowwater,

Ulster Ulster (; ga, Ulaidh or ''Cúige Uladh'' ; sco, label= Ulster Scots, Ulstèr or ''Ulster'') is one of the four traditional Irish provinces. It is made up of nine counties: six of these constitute Northern Ireland (a part of the United Kin ...

Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...

in 1903) produced leaves fully in width. The seeds germinate best in very moist, but not wet, conditions and temperatures of 22–29 °C. Only slightly smaller is ''G. masafuerae'' of the Juan Fernandez Islands off the

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

an coast. They can have leaves up to in width on stout leaf stalks long and thick according to Skottsberg. These leafstalks or petioles are the thickest of any dicot, and probably also the most massive. On nearby Isla Más Afuera, ''G. peltata'' frequently has an upright trunk to in height by thick, bearing leaves up to wide. The Hoja de Pantano (''G. magnifica'') of the

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the ...

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

bears the largest leaf buds of any plant; up to long and thick. The

succulent In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

leaf stalks are up to long. The massive

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

of small, reddish

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s is up to long and weighs about 13 kg. The flowers of Gunnera species are dimerous ( two sepals, two petals (or none) . two stamens (or one), and two carpels. Other giant ''Gunnera'' species within the subgenus ''Panke'' are found throughout the

Neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

and

. ''Gunnera insignis'' is also known by the name "poor man's umbrella" in

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

. Outside of the subgenus ''Panke'', most of the more basal ''Gunnera'' species have small-to-medium-sized leaves. There are some species with moderately large leaves in

(''G. perpensa'', in the subgenus ''Perpensum'') and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

(''G. macrophylla'', in the subgenus ''Pseudogunnera''), but the majority of more basal species are low-lying, mat-forming plants with small leaves. There are several small species are found in

, notably ''G. albocarpa'', with leaves only 1–2 cm long, and also in South America, with ''G. magellanica'' having leaves 5–9 cm wide on stalks 8–15 cm long. The most basal species in the genus, ''G. herteri'' of Brazil, also has small leaves. Some fossil leaf impressions of ''Gunnera'' from the

have large leaves akin to those of ''Panke'', and the most basal extant species within ''Panke'' (''G. mexicana'') is the most northern member. For this reason, it has been suggested that ''Panke'' originates from South American ''Gunnera'' that colonized North America during the Cretaceous and grew into giant forms, with the remaining South American ''Gunnera'' evolving into the subgenus ''Misandra'', with a low-lying, matlike growth. During the Cenozoic, the North American ''Panke'' would have colonized

and retreated southwards on the mainland before recolonizing South America. However, more recent phylogenetic evidence suggests that ''Misandra'' and ''Panke'' diverged only 15 million years ago, much too recent to assign the Cretaceous ''Gunnera'' to ''Panke''. Due to this, the large-leaved Cretaceous ''Gunnera'' from North America may represent a distinct lineage that

convergently evolved Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

giant leaves similar to those of ''Panke'', but did not leave any descendants. ''''

Species

Species list adapted from the

World Checklist of Selected Plant Families The World Checklist of Selected Plant Families (usually abbreviated to WCSP) is an "international collaborative programme that provides the latest peer reviewed and published opinions on the accepted scientific names and synonyms of selected pla ...

; * '' Gunnera aequatoriensis'' - Ecuador * '' Gunnera albocarpa'' - New Zealand * ''

Gunnera annae ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are various ...

'' - Peru, Bolivia * '' Gunnera antioquensis'' L.E.Mora - Colombia * '' Gunnera apiculata'' - Bolivia, Argentina * '' Gunnera arenaria'' - New Zealand * '' Gunnera atropurpurea'' - Colombia, Ecuador * '' Gunnera berteroi'' - Bolivia, Argentina, Chile * '' Gunnera bogotana'' - Colombia * '' Gunnera bolivari'' - Peru, Ecuador * '' Gunnera bracteata'' - Robinson Crusoe Island in Chile * '' Gunnera brephogea'' - Colombia, Ecuador, Peru * '' Gunnera caucana'' - Colombia * '' Gunnera colombiana'' - Colombia, Ecuador * '' Gunnera cordifolia'' - Tasmania * '' Gunnera cuatrecasasii'' - Colombia * '' Gunnera densiflora'' - New Zealand * '' Gunnera dentata'' - New Zealand * '' Gunnera diazii'' - Colombia * '' Gunnera flavida'' - New Zealand * '' Gunnera garciae-barrigae'' - Colombia * '' Gunnera hamiltonii'' - New Zealand * '' Gunnera hernandezii'' - Colombia * '' Gunnera herteri'' Osten - Uruguay, S Brazil * ''

Gunnera insignis ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are various ...

'' - Panama, Nicaragua, Costa Rica * '' Gunnera kauaiensis'' - Kauai in Hawaii * '' Gunnera killipiana'' - Chiapas, Guatemala, Honduras * '' Gunnera lobata'' - Tierra del Fuego * '' Gunnera lozanoi'' - Colombia * '' Gunnera macrophylla'' - Papuasia, Indonesia, Philippines * '' Gunnera magellanica'' - W + S South America, Falkland Is. * '' Gunnera magnifica'' - Colombia * ''

'' - S Brazil * '' Gunnera margaretae'' - Peru, Bolivia * '' Gunnera masafuerae'' - Alejandro Selkirk Island (Isla Mas Afuera) in Chile * '' Gunnera mexicana'' - Veracruz, Chiapas * ''

Gunnera mixta ''Gunnera mixta'' is a species of ''Gunnera ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely ...

'' - New Zealand * '' Gunnera monoica'' - New Zealand incl Chatham Islands * '' Gunnera morae'' - Colombia * '' Gunnera peltata'' - Robinson Crusoe Island in Chile * ''

Gunnera perpensa ''Gunnera perpensa'', is a species of ''Gunnera'' found in Madagascar. References

{{Taxonbar, from=Q15341337 Gunnera, perpensa Endemic flora of Madagascar Taxa named by Carl Linnaeus ...

'' - Africa, Madagascar * '' Gunnera peruviana'' - Ecuador, Peru * '' Gunnera petaloidea'' - Hawaii * '' Gunnera pilosa'' - Peru, Bolivia, Ecuador * ''

Gunnera pittieriana ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are various ...

'' - Venezuela * '' Gunnera prorepens''- New Zealand * '' Gunnera quitoensis'' - Ecuador * '' Gunnera reniformis'' - New Guinea * '' Gunnera saint-johnii'' - Colombia * '' Gunnera sanctae-marthae'' - Colombia * ''

Gunnera schindleri ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are various ...

'' - Bolivia, Argentina * '' Gunnera schultesii'' - Colombia * '' Gunnera silvioana'' - Ecuador, Colombia * '' Gunnera steyermarkii'' - Venezuela * ''

Gunnera strigosa ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are variou ...

''- New Zealand * '' Gunnera tacueyana'' - Colombia * '' Gunnera tajumbina'' - Ecuador, Colombia * '' Gunnera talamancana'' - Costa Rica, Panama * '' Gunnera tamanensis'' - Colombia * ''

Gunnera tayrona ''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are various ...

'' - Colombia * '' Gunnera tinctoria'' - Chile, Argentina * '' Gunnera venezolana'' - Venezuela

Cyanobacterial symbiosis

At least some species of ''Gunnera'' host

endosymbiotic An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within ...

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, bl ...

such as '' Nostoc punctiforme''. The cyanobacteria provide fixed nitrogen to the plant, while the plant provides fixed carbon to the microbe. The bacteria enter the plant via glands found at the base of each leaf stalk and initiate an intracellular symbiosis which is thought to provide the plant with fixed nitrogen in return for fixed carbon for the bacterium. This intracellular interaction is unique in flowering plants and may provide insights to allow the creation of novel symbioses between crop plants and cyanobacteria, allowing growth in areas lacking fixed nitrogen in the soil.

Uses

The stalks of '' G. tinctoria'' (''nalcas''), from southern

and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

, are edible. Their principal use is fresh consumption, but also they are prepared in salads, liquor or marmalade. Leaves of this species are used in covering curanto (a traditional Chilean food). ''Gunnera perpensa'' is a source of traditional medicine in southern Africa, both in veterinary and human ailments, largely in obstetric and digestive complaints, but also as a wound dressing. It also is eaten in various ways, largely the petioles, flower stalks and leaves, fresh and raw, preferably with skins and fibre removed, which is said to remove bitterness, but also cooked. The plant also is said to be used in making a beer.

References

External links

* *
Gunneraceae
in L. Watson and M.J. Dallwitz (1992 onwards).
The families of flowering plants
: descriptions, illustrations, identification, information retrieval.'' Version: 21 May 2006
http://delta-intkey.com

links at CSDL

The Gunnera Gallery

* Global Invasive Species databas
Gunnera tinctoria
* Medicinal plant detail
Gunnera perpensa
* {{Taxonbar, from1=Q133625, from2=Q2338324 Eudicot genera Medicinal plants Taxa named by Carl Linnaeus