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.[1] The name Dysoxylum derives from the Greek word ‘Dys’ meaning "bad" referring to "ill-smelling" and ‘Xylon’ meaning "wood".[3][4]
Eight species are native to the Indian subcontinent.[5] 15 species are native to Indochina,[6] and 6 are native to southern China.[7] 13 species are native to Malesia,[8] and seven species to Papuasia (New Guinea, the Bismarck Archipelago, and Solomon Islands) and the Santa Cruz Islands.[9]
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.[5][12][13]
Habitatsedit
These trees are important components of the native tropical forests of their range, such as New Guinea and the tropical forests of northern Australia.[12][11]
In this region, more than forty different species grow naturally, from the lowlands to the mountains.[12] In New Guinea, D. enantiophyllum and an undescribed taxon have records of growing up to about 3,000 m (9,800 ft) elevation.[12]
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 1,700 m (5,600 ft) elevation.[14]
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 independtly 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.[13] In Indian tradition and culture oil is extracted from the seeds Dysoxylum malabaricum, which has wide beneficial application.[16]
Taxonomyedit
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.[2]
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.[1][2]
Didymocheton bijugus(Labill.) Holzmeyer & Mabb. (as Dysoxylum bijugum(Labill.) Seem., D. leratianumGuillaumin, D. parvifoliumC.DC., D. patersonianum(Endl.) F.Muell., and D. unijugumC.DC.)
Didymocheton fraserianus(A.Juss.) Mabb. & Hauenschild (as Dysoxylum becklerianumC.DC., D. fraserianum(A.Juss.) Benth., D. lessertianum(A.Juss.) Benth., and D. ptychocarpumRadlk.)
Didymocheton gaudichaudianusA.Juss. (as Dysoxylum albiflorumC.DC., D. amooroidesMiq., D. bakerarumGuillaumin, D. betcheiC.DC., D. blancoiVidal,[40]D. decandrum(Blanco) Merr., D. gaudichaudianum(A.Juss.) Miq., D. intermediumMerr. & L.M.Perry, D. macrophyllumTeijsm. & Binn., D. maotaReinecke, D. otophorumMiq., D. pubescensTeijsm. & Binn., D. quaifeiC.DC., D. rufum var. glabrescensBenth., D. salutareFern.-Vill., D. spanogheiMiq., and D. vestitumWarb.)
Didymocheton mollis(Miq.) Holzmeyer & Hauenschild (as Dysoxylum molleMiq., D. mollissimum subsp. molle(Miq.) Mabb., and Dysoxylum velutinumKoord.)
Didymocheton mollissimus(Spreng.) Mabb. (as D. alliarum(Buch.-Ham.) N.P.Balakr., D. filicifoliumH.L.Li, D. floribundumMerr., D. hainanenseMerr., D. hainanense var. glaberrimumF.C.How & T.C.Chen, D. hamiltoniiHiern in J.D.Hooker, D. leptorrhachisHarms, D. mollissimum(Spreng.) Blume ex G.Don, D. octandrum(Blanco) Merr., D. schizochitoides(Turcz.) C.DC., and D. teysmanniiC.DC.)
Didymocheton roseus(Baill.) Holzmeyer & Mabb. (as Dysoxylum comptoniiBaker f., D. coriaceumGuillaumin, D. couveleenseGuillaumin, D. franciiC.DC. ex Bonati, D. gamosepalumBaker f., D. pancheri(Baill.) C.DC., D. pancheri var. subsessilifoliumC.DC., D. robertsiiC.DC.D. roseumC.DC., and Dysoxylum vieillardiiC.DC.)
Didymocheton rufescens(Vieill. ex Pancher & Sebert) Harms (as Dysoxylum rufescensVieill. ex Pancher & Sebert)
Epicharis parasitica(Osbeck) Mabb. (as Dysoxylum brachypodumBaker f., D. callianthumMerr. & L.M.Perry, D. caulostachyumMiq., D. densevestitumC.T.White & W.D.Francis, D. fissumC.T.White & W.D.Francis ex Lane-Poole, D. fragransElmer, D. glochidioidesElmer ex Merr., D. leytenseMerr., D. loheriMerr., D. longicalicinumC.DC., D. longiflorumMerr., D. longipetalumC.DC., D. megalanthumHemsl., D. novoguineeuseWarb., D. parasiticum(Osbeck) Kosterm.,[52][53][54]D. ramiflorumMiq., D. richardsonianumMerr. & L.M.Perry, D. robinsoniiMerr., D. roemeriC.DC., D. rumphiiMerr., D. schiffneriF.Muell., D. sericeum(Blume) Adelb., and D. speciosum(A.Juss.) Miq.)
^ abcHolzmeyer, Laura; Hauenschild, Frank; Mabberley, David J.; Muellner-Riehl, Alexandra N. (2021). "Confirmed polyphyly, generic recircumscription and typification of Dysoxylum (Meliaceae), with revised disposition of currently accepted species". Taxon. 70 (6): 1248–1272. doi:10.1002/tax.12591.
^Cooper, Wendy; Cooper, William T. (June 2004). "Dysoxylum Blume". Fruits of the Australian Tropical Rainforest. Clifton Hill, Victoria, Australia: Nokomis Editions. p. 287. ISBN 9780958174213. Archived from the original on 9 April 2013. Retrieved 7 April 2014.
^ ab
Boland, D. J.; Brooker, MIH; Chippendale, GM; N Hall; BPM Hyland; RD Johnston; DA Kleinig; MW McDonald; JD Turner (Dec 2006). Forest Trees of Australia. CSIRO Publishing. pp. 120–. ISBN 978-0-643-09894-7. Retrieved 9 April 2013.
^ abWorld Checklist of Vascular Plants (WCVP) checklist builder; search results for Indian Subcontinent (region) + Dysoxylon (genus). Accessed 28 February 2024.
^World Checklist of Vascular Plants (WCVP) checklist builder; search results for Indo-China (region) + Dysoxylon (genus). Accessed 17 February 2024.
^World Checklist of Vascular Plants (WCVP) checklist builder; search results for China (region) + Dysoxylon (genus). Accessed 17 February 2024.
^World Checklist of Vascular Plants (WCVP) checklist builder; search results for Malesia (region) + Dysoxylon (genus). Accessed 17 February 2024.
^World Checklist of Vascular Plants (WCVP) checklist builder; search results for Papuasia (region) + Dysoxylon (genus). Accessed 17 February 2024.
^World Checklist of Vascular Plants (WCVP) checklist builder; search results for Australia (region) + Dysoxylon (genus). Accessed 17 February 2024.
^ abcdMabberly, D.J.; Pannell, C.M.; Sing, A.M. (1995). Flora Malesiana Series I—Spermatophyta. Leiden: Rijksherbarium/Hortus Botanicus. pp. 1–388.
^ abParcha, V.; Gahlot, M.; Kaur, J.; Tomar, Y. (2004). "A review on phytochemical and pharmacological studies of Dysoxylum species". Journal of Natural Remedies. 4 (1). Bangalore: Natural Remedies Private Ltd.: 1–11. ISSN 0972-5547. Archived from the original on 30 July 2013. Retrieved 9 April 2013.
^"Dysoxylum malabaricum". WoodworkersSource.com. Archived from the original on 8 July 2020. Retrieved 10 April 2013.
^"Exploring the "Bio- Cultural" Heritage in Conservation of 5 Rare, Endemic & Threatened (RET) Tree Species of Western Ghats of Kerala" (PDF). CMS Date IUCN Organization. Retrieved 9 April 2013.
^
Yuncker, T. G. (July 1959). "Dysoxylum tongense A.C.Sm". Plants of Tonga(Digitised, online, via hathitrust.org). B. P. Bishop Museum Bulletin. Vol. 220. Honolulu, Hawaii: B. P. Bishop Museum. p. 158. Retrieved 7 Nov 2013.
Mabberley, David J.; Pannel, C. M.; Sing, A. M. (1995). "Dysoxylu". Flora Malesiana(Digitised, online). Series I, Spermatophyta : Flowering Plants: Vol. 12 pt. 1: Meliaceae. Leiden, The Netherland: Rijksherbarium / Hortus Botanicus, Leiden University. pp. 61–133. ISBN 90-71236-26-9. Retrieved 20 January 2021.
Peng, Hua; Mabberley, David J. (2008). Wu, Z. Y.; Raven, P. H. (eds.). "Dysoxylum Blume". Flora of China. Online version. eFloras.org. Beijing and St. Louis, MO: Science Press and Missouri Botanical Garden Press. Retrieved 26 June 2013.