Dear Battara or Jose'; the flag is a Sulu panji or Sulu sultanate flag dated 1900 circa; this kind of flag appears in Sulu archipelago after 1899/1900; about the symbol you mentioned it's a great enigma!!! Someone say the symbol on it is a comb meaning the female world (the male world is symbolized by a kris );we can find out these symbols ion some native (samal or Badjao flags) not on a Sultanate flag for some other scholars the white circle with the symbol on it symbolized a shield; i think that's not correct : we have many other Sulu flags with the circle and one or two stripes vertically or horizontally placed , so what's the meaning of them ? why they are so different from the symbol you mentioned ? "Your" symbol can represented a shield , better the back of the shield but we can't understand the reasons why they placed a shield showing its back side.... . Few researchers say that the circle can symbolize the moon just... once again what's the symbol (black or blue ? ) on it ? As you can see at present we have so many interpretations and so many few evidences; anyway, i hope i , or someone else will be able to explain this symbol very soon.
I have one brought back by my grandfather (Troop K, 5th Cavalry) and he told my grandmother it was a cotton boll. Now, whether he heard that from another Gringo over there, or got it from :the horse's mouth," I do not know. Those with any green on them seem to be reinforcing the Muslim influence.