All parts of
Carolina Jessamine (Gelsemium sempervirens) contain highly toxic alkaloids.
From Wikipedia:
~ All parts of this plant contain the toxic strychnine-related alkaloids gelsemine and gelseminine and should not be consumed. The sap may cause skin irritation in sensitive individuals. Children, mistaking this flower for honeysuckle, have been poisoned by sucking the nectar from the flower.The nectar is also toxic to honeybees, which may cause brood death when gathered by the bees.
From Lady Bird Johnson Wildflower Center:
~ The flowers, leaves, and roots are poisonous and may be lethal to humans and livestock. The species nectar may also be toxic to honeybees if too much is consumed and honey made from Carolina Jessamine nectar may be toxic to humans.