When the margins of sepals or petals overlap one another without any particular direction, the condition is termed as (a) vexillary (b) imbricate (c) twisted (d) valvate.
Option B Aestivation is the arrangements of accessory floral organs (sepals or petals) in relation to one another in floral bud. It may be of open, valvate, twisted or imbricate type. In imbricate aestivation there is an irregular overlapping of petals by one another. It has three subtypes besides imbricate proper i.e., quincuncial, ascending imbricate and descending imbricate or vexillary. Cassia, Pisum, etc., show imbricate aestivation.
