1) The petals in a bud of Portulaca grandiflora growing in nature start to make the first movement before 5 o'clock in the morning.
2) The flowers of Portulaca begin to open simultaneously. The opening movement of the flowers is not due to the influence of the sun rays, but is due to the rise in temperature.
3) The degree of flowering (the opening angle) fluctuates with changing temperature during the daytime.
4) When a bud is transferred to a place of higher temperature, it suddenly begins to open at any time in the early morning.
5) When a flower already opened is transferred to a place of lower temperature it shuts. However, when thereafter it is transferred to a place of higher temperature it opens again.
6) The bigger the difference in temperature, the quicker the flower opens. The petals can react to a difference of 2 degrees.
7) Light is not required for the opening movement of the Portulaca flower. The strong light shows rather a retarding action on the opening of the petal.