I am sorry, no guide to size of flowers, tree is quite large! I'll look and see whether I have a photo which carries more information. Good view of leaves, flowers are distinctive. Thanks, Matt
Thank you, probably agree - Flowers buds bright pink, flowers pink in morning fading to white in the evening, with large yellow stamen. I'll see what the seed pods look like, just in case it is Cassia nodosa (Cassia javanica ssp. nodosa) as the trees looks rather tall and the petals are not so rounded.
I'm not so sure if we have C. nosoda in Thailand but we certainly have C. javanica whose flowers are deep pink and it blooms with all the leaves on. C. bakeriana tends to have no leaves during the flowering period.
Many thanks Kadai, that is good information ! Certainly the tree has all it's leaves, the buds start strong pink - but the flowers are definitely pretty pale by evening. Picture here Cassia nodosa Matt