Dysoxylum

Dysoxylum is a genus of rainforest trees and shrubs in the flowering plant family Meliaceae. About 34 species are recognised in the genus, distributed from India and southern China, through southeast Asia to New Guinea, Solomon Islands, and Australia.Template:R The name Dysoxylum derives from the Greek word ‘Dys’ meaning "bad" referring to "ill-smelling" and ‘Xylon’ meaning "wood".

Distribution

The genus ranges from the Indian subcontinent to Indochina, southern China, Malesia, New Guinea and the Solomon and Santa Cruz Islands, and northern and eastern Australia.

Eight species are native to the Indian subcontinent. 15 species are native to Indochina, and 6 are native to southern China. 13 species are native to Malesia, and seven species to Papuasia (New Guinea, the Bismarck Archipelago, and Solomon Islands) and the Santa Cruz Islands.

Four species – Dysoxylum acutangulum, D. latifolium, D. oppositifolium, and D. pumilum – are native to Australia. They grow in northwestern New South Wales, the humid east coast regions of Queensland including the wet tropics rainforests region of northeastern Queensland and Cape York Peninsula, and the northern parts of the Northern Territory and Western Australia.

In the Indian subcontinent, including India, Bhutan, Nepal, and Sri Lanka, large trees of the genus Dysoxylum grow naturally in forests from lowlands to mid-elevation mountains. Eight species are native to the region. D. beddomei, D. malabaricum, D. purpureum, and D. swaminathanianum are endemic to southwestern India. D. cyrtobotryum, D. gotadhora, D. grande, and D. pallens are native to the Indian subcontinent and southeast Asia.

Habitats

These trees are important components of the native tropical forests of their range, such as New Guinea and the tropical forests of northern Australia. In this region, more than forty different species grow naturally, from the lowlands to the mountains. In New Guinea, D. enantiophyllum and an undescribed taxon have records of growing up to about Template:Convert elevation.

In the forests of the region of China, India, Sri Lanka and the adjacent Himalayas including Bhutan and Nepal, about fourteen recorded different species grow naturally from the lowlands to the mountains up to Template:Convert elevation.

In India, Dysoxylum malabaricum is known by many other names such as Indian white cedar, (ಬಿಳಿದೇವದಾರು), Bombay white cedar, Velley agile, Porapa, Vella agil, and (ದೇವರಿಗೆ). It grows in the evergreen forest regions of Western Ghats, North Kanara, Coorg, Anaimalai Hills, and Travancore regions.

Uses

File:Dysoxylum ficiforme.jpg

Dysoxylum gotadhora, 20 Dec 2007, India

The Australian species were prized for their wood which is a rich red in colour and was widely used in the furniture trade. The common timber name for the Australian species is the rose mahogany. The New Zealand species, Kohekohe (D. spectabile), is sometimes known as New Zealand mahogany, because its wood is light, strong and polishes to a fine red colour.

Rohitukine (C16H19O5N), a chromane alkaloid, was first reported from Amoora rohituka (Roxb.) Wight & Arn. (Meliaceae) and then from D. binectariferum (aka D. gotadhora) Rohitukine exhibits both anti-inflammatory as well as immuno-modulatory properties besides acting as an anticancer compound. Rohitukine is an important precursor for the semi-synthetic derivative, flavopiridol (C21H20Cl NO5).

In India, apart from its economic importance for building and furniture making, it is an important ingredient in Ayurvedic Medicine as many species have curative qualities taken independently or as an ingredient of a medicinal mixture. Some of the uses in Ayurveda reported are; Wood decoction of D. malabaricum to cure rheumatism and its oil is used to cure eye and ear diseases; a few species are used to cure inflammation, cardio-disorder, CNS disorder and also tumor. In Indian tradition and culture oil is extracted from the seeds Dysoxylum malabaricum, which has wide beneficial application.

Taxonomy

The genus Dysoxylum was erected in 1825 by the German-Dutch botanist Carl Ludwig Blume to accommodate some newly discovered plant species from Java. Over the years many changes were made to the genus, and by the late 20th century it was clear that Dysoxylum had become polyphyletic. A 2021 revision of the genus (which by then had come to include 94 species) confirmed the polyphyly and the authors reinstated several genera which had previously been considered synonyms of Dysoxylum – Didymocheton, Epicharis, Goniocheton, Prasoxylon, and Pseudocarapa – in order to accommodate their findings.Template:R

The authors (Holzmeyer et al.) proposed a circumscription (i.e. a concept of included species) of the genus that included 28 species, plus one subspecies. Following the publication of the 2021 paper, Plants of the World Online (POWO) revised their own circumscription of the genus to include 34 species. Of the 28 species proposed by Holzmeyer et al., only 23 are accepted by POWO, and there are 11 species included by POWO that were not proposed by Holzmeyer et al.Template:R

Species

34 species are currently accepted by Plants of the World Online. Template:Div col

• Dysoxylum acutangulum Template:Au
  • subsp. acutangulum – Peninsular Thailand, Malesia: Sumatra, Malay Peninsula, Borneo, Philippines
  • subsp. foveolatum Template:Au – New Guinea, Solomon Is., Queensland, NT, N. Australia; Malesia: Sumatra, Java, Flores, Timor, Moluccas
• Dysoxylum beddomei Template:Au – India
• Dysoxylum brachybotrys Template:Au – Malesia: Borneo, Philippines
• Dysoxylum carolinae Template:Au – Vietnam; Malesia: Sumatra, Malay Peninsula, Borneo
• Dysoxylum cupuliforme Template:Au – south-central China (Yunnan)
• Dysoxylum cyrtobotryum Template:Au – SE Asia to Malesia: Nicobar Is., Andaman Is., Sumatra, Malay Peninsula, Borneo, Java, Bali, Flores, Philippines
• Dysoxylum enantiophyllum Template:Au – New Guinea
• Dysoxylum flavescens Template:Au – Malesia: Sumatra, Malay Peninsula, Borneo
• Dysoxylum gotadhora Template:Au – S. China, Hainan, Bhutan, India, Laos, Nepal, Thailand, Vietnam - Syn. Dysoxylum ficiforme Template:Au – India
• Dysoxylum grande Template:Au; Synonym: D. verruculosum – NE India (Assam), S. China, Vietnam, Thailand, Hainan, Bhutan; Malesia: Sumatra, Malay Peninsula, Borneo, Philippines
• Dysoxylum hoaense Template:Au – Vietnam
• Dysoxylum juglans Template:Au – Laos, Vietnam
• Dysoxylum kaniense Template:Au – New Guinea, Solomon Is.
• Dysoxylum latifolium Template:Au – New Guinea, Solomon Is., Queensland wet tropics, Cape York, NT, Western Australia
• Dysoxylum laxiracemosum Template:Au – south-central China (southern Yunnan)
• Dysoxylum macrocarpum Template:Au – Thailand; Malesia: Sumatra, Malay Peninsula, Borneo, Sulawesi, Java, Philippines
• Dysoxylum magnificum Template:Au – SE Sumatra, Borneo
• Dysoxylum malabaricum Template:Au – Template:Langx, India
• Dysoxylum medogense Template:Au – southeastern Tibet
• Dysoxylum middletonianum Template:Au – eastern New Guinea
• Dysoxylum oliveri Template:Au – northern Myanmar
• Dysoxylum oppositifolium Template:Au, pink mahogany – New Guinea, Solomon Is., Queensland wet tropics, Cape York, NT; Malesia incl.: Borneo, Philippines, Sumba, Flores
• Dysoxylum pachyrhache Template:Au – Borneo
• Dysoxylum pallens Template:Au – S. China, Hainan, Bhutan, Cambodia, India, Burma, Thailand
• Dysoxylum papillosum Template:Au – Peninsular Thailand; Malesia: Malay Peninsula, Borneo
• Dysoxylum perryanum Template:Au – Vietnam
• Dysoxylum poilanei Template:Au – southern Vietnam
• Dysoxylum pumilum Template:Au – Queensland wet tropics endemic
• Dysoxylum purpureum Template:Au – southern India
• Dysoxylum quadrangulatum Template:Au – Sulawesi
• Dysoxylum randianum Template:Au – New Guinea
• Dysoxylum rubrocostatum Template:Au - Vietnam
• Dysoxylum rugulosum Template:Au – Malesia: Sumatra, Malay Peninsula, Borneo
• Dysoxylum swaminathanianum Template:Au – India (Kerala)

Formerly placed here

• Didymocheton aliquantulus Template:Au (as Dysoxylum aliquantulum Template:Au)
• Didymocheton aneityensis Template:Au (as Dysoxylum aneityense Template:Au)
• Didymocheton annae Template:Au (as Dysoxylum annae Template:Au)
• Didymocheton bijugus (Labill.) Holzmeyer & Mabb. (as Dysoxylum bijugum Template:Au, D. leratianum Template:Au, D. parvifolium Template:Au, D. patersonianum Template:Au, and D. unijugum Template:Au)
• Didymocheton boridianus Template:Au (as Dysoxylum boridianum Template:Au)
• Didymocheton canalensis Template:Au (as Dysoxylum canalense Template:Au)
• Didymocheton fraserianus Template:Au (as Dysoxylum becklerianum Template:Au, D. fraserianum Template:Au, D. lessertianum Template:Au, and D. ptychocarpum Template:Au)
• Didymocheton gaudichaudianus Template:Au (as Dysoxylum albiflorum Template:Au, D. amooroides Template:Au, D. bakerarum Template:Au, D. betchei Template:Au, D. blancoi Template:Au, D. decandrum Template:Au, D. gaudichaudianum Template:Au, D. intermedium Template:Au, D. macrophyllum Template:Au, D. maota Template:Au, D. otophorum Template:Au, D. pubescens Template:Au, D. quaifei Template:Au, D. rufum var. glabrescens Template:Au, D. salutare Template:Au, D. spanoghei Template:Au, and D. vestitum Template:Au)
• Didymocheton hornei Template:Au (as Dysoxylum hornei Template:Au)
• Didymocheton huntii Template:Au (as Dysoxylum huntii Template:Au)
• Didymocheton kouiriensis Template:Au (as Dysoxylum kouiriense Template:Au)
• Didymocheton lenticellaris Template:Au (as Dysoxylum lenticellare Template:Au)
• Didymocheton loureiroi Template:Au (as Dysoxylum loureiroi Template:Au)
• Didymocheton macranthus Template:Au (as Dysoxylum macranthum Template:Au)
• Didymocheton macrostachyus Template:Au (as Dysoxylum macrostachyum Template:Au)
• Didymocheton minutiflorus Template:Au (as Dysoxylum minutiflorum Template:Au)
• Didymocheton mollis Template:Au (as Dysoxylum molle Template:Au, D. mollissimum subsp. molle Template:Au, and Dysoxylum velutinum Template:Au)
• Didymocheton mollissimus Template:Au (as D. alliarum Template:Au, D. filicifolium Template:Au, D. floribundum Template:Au, D. hainanense Template:Au, D. hainanense var. glaberrimum Template:Au, D. hamiltonii Template:Au, D. leptorrhachis Template:Au, D. mollissimum Template:Au, D. octandrum Template:Au, D. schizochitoides Template:Au, and D. teysmannii Template:Au)
• Didymocheton muelleri Template:Au (as Dysoxylum muelleri Template:Au)
• Didymocheton multijugus Template:Au (as Dysoxylum seemannii Template:Au)
• Didymocheton myriandrus Template:Au (as Dysoxylum myriandrum Template:Au)
• Didymocheton nutans Template:Au (as Dysoxylum nutans Template:Au)
• Didymocheton pachyphyllus Template:Au (as Dysoxylum pachyphyllum Template:Au)
• Didymocheton pachypodus Template:Au (as Dysoxylum pachypodum Template:Au)
• Didymocheton papuanus Template:Au (as Dysoxylum micranthum Template:Au and D. papuanum Template:Au)
• Didymocheton pauciflorus Template:Au (as Dysoxylum biflorum Template:Au, D. laxum Template:Au, and D. pauciflorum Template:Au)
• Didymocheton pettigrewianus Template:Au (as Dysoxylum pettigrewianum Template:Au)
• Didymocheton phaeotrichus Template:Au (as Dysoxylum phaeotrichum Template:Au)
• Didymocheton roseus Template:Au (as Dysoxylum comptonii Template:Au, D. coriaceum Template:Au, D. couveleense Template:Au, D. francii Template:Au, D. gamosepalum Template:Au, D. pancheri Template:Au, D. pancheri var. subsessilifolium Template:Au, D. robertsii Template:Au D. roseum Template:Au, and Dysoxylum vieillardii Template:Au)
• Didymocheton rufescens Template:Au (as Dysoxylum rufescens Template:Au)
• Didymocheton rufus Template:Au (as Dysoxylum rufum Template:Au)
• Didymocheton sessilis Template:Au (as Dysoxylum sessile Template:Au)
• Didymocheton setosus Template:Au (as Dysoxylum setosum Template:Au)
• Didymocheton sparsiflorus Template:Au) (as Dysoxylum sparsiflorum Template:Au)
• Didymocheton spectabilis Template:Au – kohekohe (syn. Dysoxylum spectabile Template:Au)
• Didymocheton stellatopuberulus Template:Au (as Dysoxylum carrii Template:Au, D. hirtum Template:Au, and D. stellatopuberulum Template:Au)
• Didymocheton tenuiflorus Template:Au (as Dysoxylum tenuiflorum Template:Au)
• Didymocheton tongensis Template:Au (as Dysoxylum tongense Template:Au)
• Didymocheton variabilis Template:Au (as Dysoxylum variabile Template:Au)
• Epicharis alata Template:Au (as Dysoxylum alatum Template:Au)
• Epicharis brevipanicula (C.DC.) Hauenschild & Mabb. (as Dysoxylum brevipaniculum Template:Au)
• Epicharis cumingiana Template:Au (as Dysoxylum cumingianum Template:Au)
• Epicharis cuneata Template:Au (as Dysoxylum angustifoliolum Template:Au, D. beccarianum Template:Au, D. cauliflorum Template:Au, D. cuneatum Template:Au, D. foxworthyi Template:Au)
• Epicharis densiflora – Bali floral emblem, known as majegau (as Dysoxylum densiflorum Template:Au)
• Epicharis gillespieana Template:Au (as Dysoxylum gillespieanum Template:Au)
• Epicharis parasitica Template:Au (as Dysoxylum brachypodum Template:Au, D. callianthum Template:Au, D. caulostachyum Template:Au, D. densevestitum Template:Au, D. fissum Template:Au, D. fragrans Template:Au, D. glochidioides Template:Au, D. leytense Template:Au, D. loheri Template:Au, D. longicalicinum Template:Au, D. longiflorum Template:Au, D. longipetalum Template:Au, D. megalanthum Template:Au, D. novoguineeuse Template:Au, D. parasiticum Template:Au, D. ramiflorum Template:Au, D. richardsonianum Template:Au, D. robinsonii Template:Au, D. roemeri Template:Au, D. rumphii Template:Au, D. schiffneri Template:Au, D. sericeum Template:Au, and D. speciosum Template:Au)
• Goniocheton arborescens Template:Au (as Dysoxylum arborescens Template:Au)
• Goniocheton brassii Template:Au (as Dysoxylum brassii Template:Au)
• Goniocheton lenticellatus Template:Au (as Dysoxylum lenticellatum Template:Au)
• Prasoxylon alliaceum Template:Au (as Dysoxylum alliaceum Template:Au)
• Prasoxylon angustifolium Template:Au (as Dysoxylum angustifolium Template:Au)
• Prasoxylon excelsum Template:Au (as Dysoxylum excelsum Template:Au)
• Prasoxylon hapalanthum Template:Au (as Dysoxylum hapalanthum Template:Au)
• Prasoxylon hongkongense Template:Au (Dysoxylum hongkongense Template:Au)
• Prasoxylon klanderi Template:Au (as Dysoxylum klanderi Template:Au)
• Prasoxylon rigidum Template:Au (as Dysoxylum rigidum Template:Au)
• Pseudocarapa championii Template:Au (as Dysoxylum championii Template:Au)
• Pseudocarapa crassa Template:Au (as Dysoxylum crassum Template:Au)
• Pseudocarapa dumosa Template:Au (as Dysoxylum dumosum Template:Au)
• Pseudocarapa inopinata Template:Au (as Dysoxylum inopinatum Template:Au)
• Pseudocarapa yunzaingensis Template:Au (as Dysoxylum yunzaingense Template:Au)