Hi Xuan...I don't have an answer for you, but I noticed my pubicalyx 'chimera' and my RHP has both square and pointed tips on the same flower. I've never noticed this before you mentioned it. Very interesting!

I do want to tell you that all three of your blooms are very beautiful...TFS!

Nancy

I'm a hoya novice, but I'm looking at my first hoya blooms just now (from last week and pubicalyx too, I think). Do you mean something else than the square look they get when the pointed tips are bent back?

The square one is 'Red Buttons'. I'm not sure which the first one is - maybe 'Bright One'. That's one that hasn't bloomed for me yet (though it's budding up as we speak - YAY!)

Denise in Omaha