Nocturnal or nocturnality refers to organisms that are primarily active at night and sleep during the day. Organisms that are not nocturnal may be diurnal (active during the day) or crepuscular (active during twlight).
Many mammals, insects, reptiles, birds, and plants are nocturnal. Examples of nocturnal organisms include: flying squirrels, mice, fireflies, moths, frogs, owls, and bats. Examples of nocturnal plants include: Moonflowers (Ipomoea alba), Night Blooming Cereus (Selenicereus), and Night Gladiolus (Gladiolus tristus).
Nocturnal Animals at IslandWood:
Check out this Nocturnal Animals Lesson
Nocturnal plants: http://www.colostate.edu/Dept/CoopExt/4dmg/Flowers/night.htm