Valvate is a type of aestivation in which the petals or sepals meet edge to edge without overlapping. Which option represents valvate aestivation?

• A. Conduplicate
• B. Imbricate
• C. Twisted aestivation
• D. Valvate

Answer: (D)

Valvate refers to an aestivation pattern where the edges of petals or sepals meet edge to edge without overlapping. Imagine the floral parts arranged so their margins touch in the same plane, forming a neat rim but none of the edges lies over another. This is different from conduplicate, where the margins are folded along the midrib and come together with one margin over the other, creating a folded, inward-facing arrangement. Imbricate shows overlapping like shingles on a roof, with parts lying partly atop one another. Twisted aestivation involves a spiral or rotated arrangement of the edges, giving a twisting appearance rather than straight edge-to-edge contact. So, the description of edge-to-edge contact without overlap matches valvate.