Idaho: Syringa

Mock orange flowers are white, 2-3 cm wide and smell like orange blossoms. Each Mock orange flower has four sepals, four petals, 1-4 cm in diameter. The plant is poisonous to cats. Mock orange flowers are commonly (but not in all species) sweetly scented.

http://www.theflowerexpert.com/content/aboutflowers/stateflowers/idaho-state-flowers
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