九層塔

植物簡介

Small herbaceous plant with erect growth habit. Gland-dotted on both surface. Small, white to light blue flowers (1 cm long) are composed of an upper and lower lip, the lower lip being slightly larger. White stamens are slightly longer than the lower lip. Terminal inflorescence is composed of flowers in whorled arrangement. The flowers are similar to that of Ocimum basilicum, but the upper lip of the calyx is shorter (2 - 3 mm long compared to 4 - 6 mm long). The inside of the calyx is also densely hairy above the fruits. Small, 1-seeded fruits are known as nutlets. In water the nutlet-wall produces a thick white cover of slimy threads within several minutes.