Pua 'ilima flower; photo by Forest & Kim Starr / USGS: Plants of Hawaii - Sida fallax (use permitted with attribution).
Official Island Flower of O'ahu
Pua 'ilima (Sida fallax) was designated the official flower of the island of O'ahu in 1988. All State Flowers
Island Flowers & Lei Materials
In addition to Hawaii's state flower, each Hawaiian island also designates an official island color and an official flower or lei material; Hawai'i - 'Ōhi'a Lehua; Maui - lokelani (pink Damask rose); O'ahu - pua 'ilima; Kaua'i - mokihana berry; Moloka'i - Pua Kukui (blossom of candlenut tree); Lana'i - kauna'oa (native dodder); Ni'ihau - pupu (tiny seashells); and Kaho'olawe - hinahina (native beach heliotrope).