(b) : The mode of arrangement of the sepals or petals with respect to one another in the floral bud is termed as aestivation. Aestivation is of different types valvate, twisted or contorted, imbricate, quincuncial, vexillary, convolute, and plicate. In valvate aestivation, sepals or petals or tepals just touch each other without any overlapping. Calotropis, tulip, Asparagus, Colchicum, Petunia, mustard and tobacco have valvate aestivation.