Such a shame that so many plants in the Botanical Garden of Rio de Janeiro are unlabeled!
Maybe someone recognizes it?

I got a step further I think, it is probably a Clerodendron sp., didn't find one yet with the same leaves..
https://www.google.be/search?q...

Lovely shrub Myriam! The form and leaves resemble Rhododendron, tropic rhodos are called Vireya Rhododendron. I found one which has similar flowers, Rhododendron tuba. How similar the flowers are to the Clerodendrum!

https://www.google.co.uk/searc...

Thanks Janet, yes indeed it could be a kind of tropical Rhodo, the leaves would match that genus better, Rhododendron tuba has a similar flower shape, I've checked the Ericaceae fam. in field museum, no match yet, it might eventually come..

I made a crop of one of the flowers..

Look at Ixora hookeri synonym Pavetta hookeri

Ixora hookeri looks very close Green, but no quite yet, thanks to your link I found a perfect match, a photo taken in the same botanical garden, probably the same shrub!
http://www.amigosjb.org.br/gal...
Unfortunately not named.. I'll have to look further

Here is something that may help you.
Click on each image and it will show you which plants are in bloom during that month.

http://translate.google.com/tr...

It gets more confusing. It could be in Rubiaceae ..

http://sura.ots.ac.cr/local/fl...

http://www.discoverlife.org/mp...

Note the brown 'balls' on the ground, there's some like it in Rubiaceae on Kew ..

http://www.kew.org/science/tro...

Looks a lot like Ixora hookeri:

http://www.ntbg.org/plants/pla...

http://cubits.org/tropicalplan...

Sorry cannot check your links now, my internet is going on and off, wonder if it has to do with the stormy weather.. I'll try again tomorrow..

The photos on the ntbg site I think cinches it as Ixora hookeri. There looks to be two different types of flowers, maybe male and female.

The photo you found Myriam is Ixora hookeri, hover your arrow over it.

Looks a lot like my Ixora odorata bush. A Madagascar native.

http://www.starrenvironmental....

http://toptropicals.com/catalo...

Okay! Ixora odorata is a symilarnym of Ixora hookeri.

http://www.catalogueoflife.org...

LOL, Dave ... the link I provided in my earlier post is of your I. hookeri plant.

Thanks Lin!

And that's what has happened to my over 50 memory.

I had a double tequila with orange & mango juice last night.

I'm trying to think of more excuses, but it's not working!

Ixora hookeri it is! You have all convinced me!

Forgot to say; the brown 'balls' on the ground are the fruits from the nearby Couroupita guianensis trees Janet! They are very big and heavy, eatable but they really stink enormously! the trees themselves are impressing beautiful though!