Corolla sympetalous, tube gradually dilated, usually 6-keeled in middle portion, then constricted abruptly to a neck and expanded to a clavate tip, lobes reflexed.

• 合瓣的花冠，逐渐膨大的筒部，通常6龙骨状的在中部部分，然后缢缩突然在颈和扩大与棍棒状端部，裂片反折。