What is this Magnolia?

Anybody can help me identify this Magnolia(Michelia)?
I have this in Thailand and believe it's from China.
The flowers bloom before sunset and are fragrant.
They last for 3 or 4 days.

 

Magnolia (Michelia) doltsopa or similar species.

 

Thanks Ron but M. doltsopa has more petals and the leaves are different.. not as hard as this one. To me, I guess it is Michelia platypetala which is now Magnolia maudiae var. platypetala. However, picture of the plant given by Magnolia Society is somewhat different which made me uncertain of what I have a home.

http://www.magnoliasociety.org/classification_matted_images/m_platypetala.html

Anybody out there can help me confirm what Magnolia I have?

Thank you.

 

Yes, I noticed that the leaves might be too heavy and blunt for that one. General aspect is the same. There might be a key around somewhere you could use, maybe a regional one that covers the species this happens to be even if not one that covers the entire section.

 

Google hit indicates this document contains a key to Michelia, if you can somehow gain access to its contents.

http://www.jstor.org/pss/2399942

 

Pic #4 looks a lot like my M. dianica - now M. laevifolia.