''Hydnophytum'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

epiphytic An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

myrmecophyte Myrmecophytes (; literally "ant-plant") are plants that live in a mutualistic association with a colony of ants. There are over 100 different genera of myrmecophytes. These plants possess structural adaptations in the form of domatia where ants ...

s (ant plants) native to

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

, the Pacific region and also extending into

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

in northern Australia. The name is derived from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''hydnon'' "tuber", and ''phyton'' "plant", after their appearance with their swollen succulent stems. The species grow in tree branches and on trunks. Like the related genus ''

Myrmecodia ''Myrmecodia'' is a genus of Epiphyte, epiphytic plants, present in Indochina, Malesia, Papuasia, and Queensland, Australia. It is one of five ant-plant genera in the family Rubiaceae, the others being ''Anthorrhiza'', ''Hydnophytum'', ''Myrme ...

'', they are known as antplants or ant-house plants. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''

Hydnophytum formicarum ''Hydnophytum formicarum'', commonly called a "Baboon's head" or "Ant plant", is an epiphyte native to Southeast Asia and is considered critically endangered in Singapore. It is a myrmecophyte as ants live in its tuber, also known as a caudex, ...

'' from the Philippines. The genus contains 55 species, of which 44 are found in and around the island of

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

. Many are poorly known, with 11 known only from the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

. They form a

symbiotic relationship Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

with ants. Ant plants provide habitats for ant colonies high up into the forest canopy, protecting them from the elements and also predators because of the spines. Hollow, smooth-walled tunnels form within the

caudex A caudex (: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is most ...

with external entrance holes, providing an above-ground home for ant colonies. Ants likewise provide defense for the plant and prevent tissue damage, swarming to defend their home if disturbed. Ant colonies also provide nutrients to the plants by leaving wastes within the tunnels inside the caudex. Special glands lining the tunnels then absorb nutriment for the plant. This symbiosis allows the plants to effectively gather nutrients (via the ants) from a much larger area than the roots ever could cover. These plants can be grown in cultivation without the ant species being present. Two species seen occasionally in cultivation are ''

Hydnophytum ferrugineum ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' from the

McIlwraith Range The McIlwraith Range is a rugged, dissected granite plateau on Cape York Peninsula of Far North Queensland, Australia. Part of the Great Dividing Range, the McIlwraith Range covers about and lies about east of the town of Coen, and north o ...

east of Coen on Cape York Peninsula, and '' H. moseleyanum'', also from Cape York. The former has a spiny swollen trunk while the latter has a smooth one. ''Hydnophytum'' is one of five ant-plant genera in the family

Rubiaceae Rubiaceae () is a family (biology), family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with Petiole ( ...

, the others being ''

Anthorrhiza ''Anthorrhiza'' is a genus of myrmecophytic flowering plants in the family Rubiaceae. It is endemic to Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises ...

'', ''

Myrmephytum ''Myrmephytum'' is a genus of myrmecophytic flowering plants in the family Rubiaceae. It is distributed from central Malesia to New Guinea. It is one of five ant-plant genera in the family Rubiaceae, the others being '' Anthorrhiza'', '' Hydno ...

'', and ''

Squamellaria ''Squamellaria'' is a genus of myrmecophytic flowering plants in the family Rubiaceae. It includes eight species native to the Solomon Islands, Vanuatu, and Fiji. It is one of five ant-plant genera in the family Rubiaceae, the others being '' ...

''.

Species

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

recognises 57 species, as follows: *''

Hydnophytum acuminicalyx ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum albertisii ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum alboviride ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum angustifolium'' *'' Hydnophytum archboldianum'' *'' Hydnophytum bracteatum'' *''

Hydnophytum buxifolium ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum caminiferum'' *'' Hydnophytum confertifolium'' *'' Hydnophytum cordifolium'' *''

Hydnophytum dauloense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum davisii ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum decipiens'' *''

Hydnophytum dentrecastense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum ellipticum'' *''

'' *''

Hydnophytum fusiforme ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum grandiflorum'' *'' Hydnophytum grandifolium'' *''

Hydnophytum hailans ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum hellwigii'' *'' Hydnophytum heterophyllum'' *''

Hydnophytum kebarense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum lauterbachii'' *'' Hydnophytum linearifolium'' *'' Hydnophytum longiflorum'' *'' Hydnophytum lucidulum'' *'' Hydnophytum magnifolium'' *''

Hydnophytum magnirubrum ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum mamberamoense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum mayuense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum microphyllum'' *''

Hydnophytum minirubrum ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum morotaiense ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum moseleyanum ''Hydnophytum moseleyanum'', commonly known as smooth ant plant, is a plant in the coffee and gardenia family Rubiaceae native to the Philippines, New Guinea and Cape York Peninsula in Australia. It is an epiphyte that inhabits mangrove forest ...

'' *''

Hydnophytum multituberosum ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum myrtifolium'' *''

Hydnophytum orichalcum ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum ovatum'' *''

Hydnophytum pauper ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum petiolatum'' *''

Hydnophytum puffii ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum radicans'' *'' Hydnophytum ramispinum'' *''

Hydnophytum reevii ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum spathulatum'' *'' Hydnophytum stenophyllum'' *'' Hydnophytum subsessile'' *''

Hydnophytum terrestris ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum tetrapterum'' *'' Hydnophytum tortuosum'' *''

Hydnophytum trichomanes ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *''

Hydnophytum valetonii ''Hydnophytum'' is a genus of epiphytic myrmecophytes (ant plants) native to Southeast Asia, the Pacific region and also extending into Queensland in northern Australia. The name is derived from the Ancient Greek ''hydnon'' "tuber", and ''phyton' ...

'' *'' Hydnophytum virgatum'' *'' Hydnophytum vitis-idaea'' *'' Hydnophytum zippelianum''

Notes

{{Taxonbar, from=Q291522 Rubiaceae genera Myrmecophytes Epiphytes Psychotrieae Taxa named by William Jack (botanist)