''Gymnostoma'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 nomenclat ...

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 Pacifi ...

. 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 continen ...

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. The ...

. In

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

, 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 Wells explai ...

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

Borneo Borneo (; id, Kalimantan) is the 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, west of Sulawesi, and eas ...

, 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 Sulawesi (), also known as Celebes (), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's eleventh-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu Ar ...

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, Maluku, Ambon to the south and various districts ('' ...

, 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 eas ...

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

, 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 capita ...

, and one endemic species each in

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

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 f ...

, 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 composed ...

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. Th ...

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 ferralsols ...

) 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'' – 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, i ...

'' – New Caledonia endemic ( Fr) * '' Gymnostoma glaucescens'' – New Caledonia endemic * '' Gymnostoma intermedium'' – New Caledonia endemic * '' Gymnostoma leucodon'' – New Caledonia endemic * '' Gymnostoma nobile'' – Borneo, Philippines * '' Gymnostoma nodiflorum'' – New Caledonia endemic * '' Gymnostoma papuanum'' – New Guinea, Solomon Islands * '' Gymnostoma poissonianum'' – New Caledonia endemic * ''

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

'' – Sulawesi, Moluccas, Ambon Island (Indonesia), Philippines, Bismarck Archipelago * '' Gymnostoma sumatranum'' – Burma, Sumatra, Borneo, Java, Sulawesi (Indonesia), W New Guinea, Philippines * '' Gymnostoma vitiense'' – Fiji endemic * '' Gymnostoma webbianum'' – 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