Oxalidaceae

Oxalis regnellii Miq.

Description: Plants exhibit nyctinastic movements (day/night movements) in which the leaflets fold up at night and are open during the day. These movements have been variously attributed to A) reduce surface area exposed to cool night air and reduce heat loss, B) reduction of amount of moonlight absorbed thus preventing false photoperiodic responses or C) to allow light during the morning and late afternoon (red/far red shift) to reach otherwise shaded leaf axils where the red/far red shift induces flower initiation.
Regardless of the explanation, these movements are a fascinating aspect of these plants.

Culture: The plants are kept in many botanical gardens and easy to rear. The vegetative propagation from rhizom bulbs is the easiest. Put a bulb in a broad flower pot containing peath rich soil and keep well watered. The light intensity should not be too high. In case of diseases it helps to cut off all leaves. The plants start soon to develop new leaves.