Naupaka flowers grow on the beach and in the mountains. They have these unusual half-flowers. According to a legend posted nearby, we can blame the volcano goddess Pele for this:
"Naupaka - the Hawaiian legend of the naupaka's small half flower
"A beautiful woman, a stranger to the village and believed to be from the mountains, fell in love with a village youth. When he rejected her and went back to his sweetheart, the beautiful woman followed him and tore him from his sweetheart's embrace. Anger blazed about the beautiful woman, and the villagers knew then that she was Pele, goddess of volcanoes.
"Pele pursued the youth into the mountains, hurling lava after him. There the gods took pity on the youth and transformed him into a half flower, the 'Mountain Naupaka.' Pele shrieked with rage and fled on a river of lava back to the ocean, seeking to overtake the maiden, whom the gods had already turned into a 'Beach Naupaka.'
"The lovers are forever separated. The half flowers of the youth still bloom alone in the mountains, and the half flowers of the maiden bloom alone on the beach."