(1) (botany) Of a floral parts in a bud where the petals are rolled vertically inwards.
(2) (general) Folded lengthwise similar to a fan; corrugated; pleated.
(1) To fold or to become bent in pleat-like fashion (i.e. parallel folds).
In plants, plicate is used to describe a form of aestivation wherein the young flower parts are rolled vertically. An example of plicate aestivation is that of the morning glory.
Word origin: Latin plicātus, perfect passive participle of plicō (I fold).