What type of plants flower when nights are longer than a critical length?

Short day plants are those that flower when nights are longer than a critical length. These plants require a certain length of uninterrupted darkness to trigger flowering, as they typically bloom in late summer or fall when the days are shorter.

This response is related to how plants use photoperiodism, which is the physiological reaction of organisms to the length of day or night. In the case of short day plants, the extended hours of darkness signal to the plant that it is time to flower, leading to the activation of specific genes that promote the flowering process.

Long day plants, on the other hand, flower when days are longer than a certain length of light, which is the opposite of short day plants. Nocturnal and diurnal plants refer to their activity patterns rather than their flowering responses to photoperiod, making them less relevant in the context of this question.