te with the margins of each piece
projecting inwards, as in the calyx of a common Virgin's-bower, Fig.
278, or

[Illustration: Fig. 278. Valvate-induplicate aestivation of calyx of
common Virgin's-bower.]

_Involute_, which is the same but the margins rolled inward, as in most
of the large-flowered species of Clematis, Fig. 279.

[Illustration: Fig. 279. Valvate-involute aestivation of same in
Vine-bower, Clematis Vitialla.]

_Reduplicate_, a rarer modification of valvate, is similar but with
margins projecting outward.

_Open_, the parts not touching in the bud, as the calyx of Mignonette.

278. When the pieces overlap in the bud, it is in one of two ways;
either every piece has one edge in and one edge out, or some pieces are
wholly outside and others wholly inside. In the first case the
aestivation is

_Convolute_, also named _Contorted_ or _Twisted_, as in Fig. 280, a
cross-section of a corolla very strongly thus convolute or rolled up
together, and in the corolla of a Flax-flower (Fig. 281), where the
petals only moderately overlap in this way. Here one edge of every petal
covers the next before it, while its other edge is covered by the next
behind it. The other mode is the

[Illustration: Fig. 280. Convolute aestivation, as in the corolla-lobes
of Oleander.]

[Illustration: Fig. 281. Diagram of a Flax-flower; calyx imbricated and
corolla convolute in the bud.]

_Imbricate_ or _Imbricated_, in which the outer parts cover or overlap
the inner so as to "break joints," like tiles or shingles on a roof;
whence the name. When the parts are three, the first or outermost is
wholly external, the third wholly internal, the second has one margin
covered by the first while the other overlaps the third or innermost
piece: this is the arrangement of alternate three-ranked leaves (187).
When there are five pieces, as in the corolla of Fig. 225, and calyx of
Fig. 281, as also of Fig. 241, 276, two are external, two are internal,
and one (the third in the spiral) has one edge covered by the outermost,
while its other edge covers the innermost; which is just the five-ranked
arrangement of alternate leaves (188). When the pieces are four, two are
outer and two are inner; which answers to the arrangement of opposite
leaves.

279. The imbricate and the convolute modes sometimes vary one into the
other, especially in the corolla.

280. In a gamopetalous corolla or gamosepalous calyx, the shape of the
tube in the bud m