Hi there,
Dont know the exact name, but going by the clusters of flowers around the stem, the flowers with a larger "lower lip" and the decussate leaves it is probably from the Labiatae or Lamiaceae family, like mint, basil.

Perhaps you can go from there,

Bye, Lin

I think it is Leucas zeylanica.

Here is a link that might be useful: Leucas zeylanica

Thanks again susanc! It looks exactly like the pics in your link