Crown flowers, or pua-kalaunu, were introduced to Hawaii from the Mideast/Far East region. (Incidentally, although the second part of its name seems to indicate it’s an import from Syria, common milkweed is considered native to North America.) The chunky “crown” in the center of the pua-kalaunu is used for making leis.
The flowers were a favorite of Queen Liliuokalani, the last reigning Hawaiian monarch.