Begonia rex hybrids (Cultivated)

Begonia rex Putz., J. Gén. Hort. 2: 141 1857. (syn: Begonia longiciliata C.Y.Wu; Platycentrum rex (Putz.) Seem.);

Images by Promila Chaturvedi (Id suggestion by Katarina Stenman) (Inserted by J.M.Garg) (For more images & complete details, click on the links)
Plant for ID-PC- 23-24.08.2015 : 3 posts by 2 authors. Attachments (2)
please identify this Begonia.
Begonia, maybe B.rex- hybrid
SK1473 27 Sep 2018 : 8 posts by 3 authors. Attachments (5)- around 550 kb each. 
Location: Hong Kong Park  
Date: 15 August 2018
Elevation: 200 ft.
Habit : Cultivated
Which Begonia sp.  ??

one of the rex begonias
nice heart shaped foliage
Not sure – a rex hybrid I think 

thanks to ... agree further classification not done
Yes ...
Begonia rex 'Cultrotum' : 13 posts by 3 authors. Attachments (5)- around 500 kb each.
Location: Hong Kong Park  
Date: 15 August 2018
Elevation: 200 ft.
Habit : Cultivated

label? never seen such red! but never say never in these days of hybrids

Yes ...
can i see the label please
Yes ... ! Attachments (1) - 767 kb
wow thank you.
you see Rex :  Begonia Rex-cultorum is a group of rex begonia hybrids, not any one species.
and that this particular cultivar had no special name, in the label. it was described  as a group way back in 1920.. by Bailey, Liberty H. Bailey.
your showing us the label enhances our knowledge here about the rex begonia hybrids. that are in cultivation and promotion by houseplant trades.
Interesting label: in the right lower quadrant they show a whole bunch of the rex begonia hybrids. all at once in their label, and say that country of origin: India.
I know you will appreciate why i keep asking for labels. you see, i have known  the rex cultivars mostly for their leaves. flowers tend to be secondary for the various botanical gardens and awarding of prizes.
please see this 2005 pdf article by RHS .
it shows mainly leaves of the various cultivars and how to judge them. not flowers. its also an interesting read, tells us the various hybrids that were made.
also missouri bot garden says this about rex begonias...
i quote:
Noteworthy Characteristics
The Rex Cultorum group – whose members commonly are known as “rex begonias” – is aptly named. These “kings” of the begonia world display wildly varied leaves streaked, bordered, spotted, and splotched by many colors. They also flower, but usually the flowers are overshadowed by the striking foliage. Most rex begonias grow from a thickened stem structure called a rhizome. They are not classed with other rhizomatous begonias, however, because of their bold leaves and more exacting growing requirements." end quote 
in final analysis
Begonia Rex-cultorum is a group name not specifies level. all rex es with spectacular leaves are that. i loved your entire rex show this month
and i have given here a short history of rex begonias and how each species level id is not possible...
this would be useful for people with curiosity about begonias of rex  descent.
SK 2342. 27 December 2019 : 10 posts by 2 authors. 7 images. from 3 mb to 7 mb each.
Location: Kalimpong, WB, India
Date: 26 November 2019 
Elevation: 1350m.
Habitat: Cultivated
Begonia rex??

Yes, B. rex. Wonderful!