Gunnera
Encyclopedia
Gunnera is a genus of herbaceous
flowering plant
s, some of them gigantic. The genus is the only member of the family Gunneraceae.
The 40-50 species vary enormously in leaf
size. Gunnera manicata
, native to the Serra do Mar mountains of southeastern Brazil
, is perhaps the largest species, with leaves typically 1.5-2 m (5-6 ft) wide, but exceptionally long, up to 3.4 m (11 ft), borne on thick, succulent leaf stalks (petioles
) up to 2.5 m (8 ft) long. It germinates best in very moist, but not wet, conditions and temperatures of 22 to 29 °C.
Only slightly smaller is G. masafuerae of the Juan Fernandez Islands
off the Chile
an coast. They can have leaves up to 2.9 m (9 ft 5 inches) in width on stout leaf stalks 1.5 m (5 ft) long and 11 cm (4.5 in) thick according to Skottsberg. On nearby Isla Más Afuera
, G. peltata frequently has an upright trunk to 5.5 m (18 ft) in height by 25–30 cm (10–12 in) thick, bearing leaves up to 2 m (6 ft 4 inches) wide. G. magnifica of the Colombia
n Andes
bears the largest leaf buds of any plant; up to 60 cm (2 ft) long and 40 cm (16 inches) thick. The succulent
leaf stalks are up to 2.7 m (8 ft 10 inches) long. The massive inflorescence
of small, reddish flower
s is up to 2.3 m (7 ft 6 inches) long and weighs about 13 kg. Other giant Gunnera species are found throughout the Neotropics and Hawaii
.
Several small species are found in New Zealand
, 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.
Commonly known as "giant rhubarb
".
This genus was named after the Norwegian botanist Johann Ernst Gunnerus.
punctiforme. 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.
(nalcas), from Southern Chile and Argentina, 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 used as a source of traditional medicine in Southern Africa.
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s, some of them gigantic. The genus is the only member of the family Gunneraceae.
The 40-50 species vary enormously in leaf
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
size. Gunnera manicata
Gunnera manicata
Gunnera manicata, or giant rhubarb, a native of Brazil, is an ornamental plant in the Gunneraceae family.The underside of the leaf and the whole stalk have spikes on them. The leaves of Gunnera grow to an impressive size...
, native to the Serra do Mar mountains of southeastern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, is perhaps the largest species, with leaves typically 1.5-2 m (5-6 ft) wide, but exceptionally long, up to 3.4 m (11 ft), borne on thick, succulent leaf stalks (petioles
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
) up to 2.5 m (8 ft) long. It germinates best in very moist, but not wet, conditions and temperatures of 22 to 29 °C.
Only slightly smaller is G. masafuerae of the Juan Fernandez Islands
Juan Fernández Islands
The Juan Fernández Islands are a sparsely inhabited island group reliant on tourism and fishing in the South Pacific Ocean, situated about off the coast of Chile, and is composed of three main volcanic islands; Robinson Crusoe Island, Alejandro Selkirk Island and Santa Clara Island, the first...
off the Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
an coast. They can have leaves up to 2.9 m (9 ft 5 inches) in width on stout leaf stalks 1.5 m (5 ft) long and 11 cm (4.5 in) thick according to Skottsberg. On nearby Isla Más Afuera
Alejandro Selkirk Island
Alejandro Selkirk Island, previously known as Isla Más Afuera and renamed after Alexander Selkirk, is the second largest and most westernly island of the Juan Fernández Islands archipelago of the Valparaíso Region of Chile...
, G. peltata frequently has an upright trunk to 5.5 m (18 ft) in height by 25–30 cm (10–12 in) thick, bearing leaves up to 2 m (6 ft 4 inches) wide. G. magnifica of the Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
n Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
bears the largest leaf buds of any plant; up to 60 cm (2 ft) long and 40 cm (16 inches) thick. The succulent
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...
leaf stalks are up to 2.7 m (8 ft 10 inches) long. The massive inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
of small, reddish flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s is up to 2.3 m (7 ft 6 inches) long and weighs about 13 kg. Other giant Gunnera species are found throughout the Neotropics and Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
.
Several small species are found in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, 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.
Commonly known as "giant rhubarb
Rhubarb
Rhubarb is a group of plants that belong to the genus Rheum in the family Polygonaceae. They are herbaceous perennial plants growing from short, thick rhizomes. They have large leaves that are somewhat triangular-shaped with long fleshy petioles...
".
Selected species
- Gunnera albocarpa
- Gunnera arenaria
- Gunnera densiflora
- Gunnera dentata
- Gunnera flavida
- Gunnera hamiltoniiGunnera hamiltoniiGunnera hamiltonii is a creeping herbaceous plant in the family Gunneraceae, with clusters of small grey-brown leaves forming a dense mat. Small green flowers are followed by red berries in the autumn....
- Gunnera kauaiensis
- Gunnera magellanica
- Gunnera magnifica
- Gunnera manicataGunnera manicataGunnera manicata, or giant rhubarb, a native of Brazil, is an ornamental plant in the Gunneraceae family.The underside of the leaf and the whole stalk have spikes on them. The leaves of Gunnera grow to an impressive size...
- Gunnera masafuerae
- Gunnera monoica
- Gunnera perpensa
- Gunnera petaloïdea
- Gunnera prorepens
- Gunnera tinctoriaGunnera tinctoriaGunnera tinctoria, the Chilean rhubarb, is a plant species native to southern Chile and neighbour zones in Argentina. It is a large-leaved perennial plant that grows up to two metres tall. It is introduced in large parts of the world as an ornamental and edible plant...
Cyanobacterial Symbiosis
In nature, all Gunnera plants form a symbiosis with a nitrogen-fixing cyanobacteria, thought to be exclusively NostocNostoc
Nostoc is a genus of cyanobacteria found in a variety of environmental niches that forms colonies composed of filaments of moniliform cells in a gelatinous sheath.The name "Nostoc" was invented by Paracelsus...
punctiforme. 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. tinctoriaGunnera tinctoria
Gunnera tinctoria, the Chilean rhubarb, is a plant species native to southern Chile and neighbour zones in Argentina. It is a large-leaved perennial plant that grows up to two metres tall. It is introduced in large parts of the world as an ornamental and edible plant...
(nalcas), from Southern Chile and Argentina, 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
Curanto
Curanto is a traditional food of Chiloé Archipelago that has spread to the southern areas of Chile and recently Argentina. It is traditionally prepared in a hole, about a meter and a half deep, which is dug in the ground...
(a traditional Chilean food).
Gunnera perpensa is used as a source of traditional medicine in Southern Africa.
External links
- The Gunnera Gallery
- Gunnera magellanica pictures from Chilebosque
- Global Invasive Species database Gunnera tinctoria
- Medicinal plant details Gunnera perpensa
- Gunnera on Achill Island http://www.achilljournal.com/index.php/2007/03/20/e15000-for-achills-wild-rhubarb/