Begonia rex

{{Short description|Species of plant in the genus Begonia}}

{{Speciesbox

|image=蛤蟆秋海棠-雄花 Begonia rex 'Red Tango' -香港公園 Hong Kong Park- (37422677575).jpg

|image_caption=Begonia rex 'Red Tango' cultivar

|image2=Begonia rex var. imperator by Adam Gatternicht.jpg

|image2_caption=Putative variety Begonia rex var. imperator by Adam Gatternicht

|genus=Begonia

|species=rex

|authority=Putz.

|synonyms_ref=

|synonyms=

• Platycentrum rex {{au|(Putz.) Seem. 1860}}
• Begonia dominiana {{au|Veitch ex J.Dix 1859}}
• Begonia marginata {{au|T.Moore 1860}}
• Begonia picturata {{au|Hend. ex Bosse 1861}}
• Begonia rex var. grandis {{au|E.J.Lowe & W.Howard 1859}}
• Begonia rex var. leopardina {{au|T.Moore 1860}}
• Begonia rex var. nebulosa {{au|E.J.Lowe & W.Howard 1860}}

}}

Begonia rex, the king begonia, is a species of flowering plant in the family Begoniaceae. It is found from Arunachal Pradesh to southeast China, and has been introduced to Bangladesh, Cuba, and Hispaniola.{{cite web |url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:105573-1 |title=Begonia rex Putz. |author= |website=Plants of the World Online |publisher=Board of Trustees of the Royal Botanic Gardens, Kew |access-date=6 July 2021 }}{{cite web |title=Begonia rex king begonia |url=https://www.rhs.org.uk/Plants/101666/i-Begonia-rex-i-(R)/Details |date=2021 |publisher=The Royal Horticultural Society |access-date=6 July 2021 |quote=Other common names; … fan plant, painted-leaf begonia }} It is a parent to over 500 cultivars in the Begonia Rex Cultorum Group of houseplants.{{cite journal |last1=Cubey |first1=Janet |last2=Wesley |first2=Wendy |date=December 2006 |title=Begonia Rex Cultorum Group |url=https://www.rhs.org.uk/Plants/PDFs/Plant-trials-and-awards/Plant-bulletins/begonia-rex.pdf |journal=RHS Plant Trials and Awards |volume=Bulletin Number 16 |pages=1–16 |access-date=6 July 2021 }} Other parents in the multitude of crosses made during the creation of the Group include Begonia annulata, B.{{nbsp}}cathayana, B.{{nbsp}}decora, B.{{nbsp}}diadema, B.{{nbsp}}dregei, B.{{nbsp}}grandis, B.{{nbsp}}hatacoa, B.{{nbsp}}palmata, and B.{{nbsp}}xanthina.

The following cultivars in the Begonia Rex Cultorum Group have gained the Royal Horticultural Society's Award of Garden Merit: 'Benitochiba', 'Carolina Moon', 'China Curl', 'Curly Fireflush', 'David Blais', 'Dewdrop', 'Emerald Beauty', 'Escargot', 'Fireworks', 'Green Gold', 'Helen Lewis', 'Hilo Holiday', 'Ironstone', 'Martin Johnson', 'Midnight Magic', 'Mikado', 'Namur', 'Orient', 'Pink Champagne', 'Princess of Hanover', 'Red Robin', 'Regal Minuet', 'Rocheart', 'Roi de Roses', 'Sal's Comet', 'Sea Serpent', 'Silver Cloud', 'Silver King', and 'Silver Queen'.{{cite web |title=AGM Plants Dec 2020 © RHS – ORNAMENTAL |url=https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf |date=December 2020 |website=rhs.org.uk |publisher=The Royal Horticultural Society |access-date=6 July 2021 }}

These plants are noted for their dark leaves with prominent silvery grey bands. When this species was introduced into cultivation, it became popular as a houseplant. Hybrids began to appear with varying leaf patterns as Rex begonias hybridize quite freely.{{Cite web |last=Shannon |first=Laughlin |date=2022-02-23 |title=Rex Begonia {{!}} Home and Garden Education Center |url=https://homegarden.cahnr.uconn.edu/factsheets/rex-begonia/ |access-date=2024-09-28 |website=University of Connecticut |language=en-US}}