Nightflowering Wild Petunia

Description

Ruellia noctiflora, the nightflowering wild petunia, is a herbaceous perennial found along the Gulf coast. Both its specific and common names derive from its habit of nocturnal flowering. In spite of the common name it is in a different family from the garden petunia. The plant grows to 16 in (41 cm) with oval, pointed, usually stalkless leaves up to 2.8 in (7.1 cm) long borne in pairs on thin, hairy, purplish stems. It bears white, trumpet-shaped, five-petalled flowers 3 in (7.6 cm) long and 4 in (10 cm) across; these open at night and fall by mid-morning, and are pollinated by hawk moths, whose long proboscises allow them to reach the nectar held at the base of the flower. The resulting fruit is a capsule .8 in (2.0 cm) long with the long style retained, resting among the five long spikey sepals. When ripe it splits in half longitudinally, discharging the seed. Unusually for the genus no cleistogamous flowers are formed.