''Gymnostoma'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of about eighteen species of trees and shrubs, constituting one of the four

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...

of the plant family

Casuarinaceae The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern Africa, Australia, Southeast Asia, Malesia, Papuasia, and the Pacific ...

. The species grow naturally in the tropics, including at high altitudes having

temperate climates In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

, in forests in the region of the western

Pacific ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

and

Malesia Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. ...

. In New Caledonia, published botanical science describes eight species found growing naturally, which botanists have not found anywhere else (endemics). Additional species have been found across

Burma Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

, Sumatra,

Borneo Borneo (; id, Kalimantan) is the List of islands by area, third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java Isl ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, Sulawesi,

Ambon Island Ambon Island is part of the Maluku Islands of Indonesia. The island has an area of and is mountainous, well watered, and fertile. Ambon Island consists of two territories: the city of Ambon to the south and various districts (''kecamatan'') o ...

, the

Moluccas The Maluku Islands (; Indonesian: ''Kepulauan Maluku'') or the Moluccas () are an archipelago in the east of Indonesia. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...

, the

Bismarck Archipelago The Bismarck Archipelago (, ) is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea. Its area is about 50,000 square km. History The first inhabitants o ...

, the

Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its ca ...

, and one endemic species each in Fiji and the

Wet Tropics of Queensland The Wet Tropics of Queensland World Heritage Site consists of approximately 8,940 km2 of Australian wet tropical forests growing along the north-east Queensland portion of the Great Dividing Range. The Wet Tropics of Queensland meets all ...

, Australia. The genus was first scientifically described by Lawrie A. S. Johnson in 1980. Many of the ''Gymnostoma'' species combinations of names ( binomials) were described by him in 1982. , a global total of eighteen species have been found and described. The majority of the species grow in rainforests, in the habitats of open, sunny, long-term gaps, from river bank (riparian) situations through to mountain top situations. In New Caledonia two endemic species ''G. chamaecyparis'' and ''G. deplancheanum'' have specialised adaptations, growing in wet "shrub

maquis Maquis may refer to: Resistance groups * Maquis (World War II), predominantly rural guerrilla bands of the French Resistance * Spanish Maquis, guerrillas who fought against Francoist Spain in the aftermath of the Spanish Civil War * The network ...

and paraforest maquis formations. ''G. chamaecyparis'' is associated with hypermagnesian soils (hypermagnesian

inceptisol Inceptisols are a soil order in USDA soil taxonomy. They form quickly through alteration of parent material. They are more developed than Entisols. They have no accumulation of clays, iron oxide, aluminium oxide or organic matter. They have an o ...

) below 600 m altitude at the base of

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are compos ...

massif In geology, a massif ( or ) is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. The term also refers to a ...

s. ''G. deplancheanum'' occurs on ferralitic

ferritic A ferrite is a ceramic material made by mixing and firing large proportions of iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc. ...

desaturated

hardpan In soil science, agriculture and gardening, hardpan or soil pan is a dense layer of soil, usually found below the uppermost topsoil layer. There are different types of hardpan, all sharing the general characteristic of being a distinct soil layer ...

or gravelly soils (

oxisol Oxisols are a soil order in USDA soil taxonomy, best known for their occurrence in tropical rain forest within 25 degrees north and south of the Equator. In the World Reference Base for Soil Resources (WRB), they belong mainly to the ferralsol ...

) on the southern massif at altitudes between 200 and 1,000 m".

Species

There are 14 formally described species: * '' Gymnostoma australianum'' – Australia endemic * ''

Gymnostoma chamaecyparis ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic ( Fr) * ''

Gymnostoma deplancheanum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic ( Fr) * ''

Gymnostoma glaucescens ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic * '' Gymnostoma intermedium'' – New Caledonia endemic * ''

Gymnostoma leucodon ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic * ''

Gymnostoma nobile ''Gymnostoma nobile'' is a species of tree endemic to northern Borneo. ''Gymnostoma nobile'' is native to heath forests, also known as kerangas forests, which grow on nutrient-poor soils. It is a nitrogen-fixing Nitrogen fixation is a chemica ...

'' – Borneo, Philippines * ''

Gymnostoma nodiflorum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic * ''

Gymnostoma papuanum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Guinea, Solomon Islands * ''

Gymnostoma poissonianum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic * ''

Gymnostoma rumphianum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, i ...

'' – Sulawesi, Moluccas, Ambon Island (Indonesia), Philippines, Bismarck Archipelago * ''

Gymnostoma sumatranum ''Gymnostoma sumatranum'' is a tree in the she-oak family, Casuarinaceae, native to Southeast Asia and the Malesia region. Distribution Areas where the tree is native include Burma, Sumatra, Borneo, Java, Kalimantan, Malaysia, Sulawesi (Indones ...

'' – Burma, Sumatra, Borneo, Java, Sulawesi (Indonesia), W New Guinea, Philippines * ''

Gymnostoma vitiense ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – Fiji endemic * ''

Gymnostoma webbianum ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high altitudes having temperate climates, in ...

'' – New Caledonia endemic There are approximately four additional species, found in New Guinea and collections preserved, that are awaiting formal description.

References

Fagales genera {{Fagales-stub