Define ptyxis.

Explanation

Rolling or folding of individual leaves is called ptyxis . There are seven types of ptyxis as follows :
1. Reclinate - When the upper half of the leaf blade is bent upon the lower half as in loquaz (Eribotrya japonica )
2 . Conduplicate - When the leaf is folded lengthwise along the mid - rib , as in guava , swee potato and camel's foot tree (Bauhinia) .
3 . Plicate or plaited - When the leaf is repeatedly folded longitudinally along ribs in a zig - zag manner , as in Borassus flabellifer .
4. Circinate - When the leaf is rolled from the apex towards the base like the tail of a dog as in ferms .
5 . Convolute - When the leaf is rolled from one margin to the other , as in banana , aroids and Indian pennywort . Musa and members of Araceae.
6 . Involute - When the two margins are rolled on the upper surface of the leaf towards the mid - rib or the centre of the leaf , as in water lily , lotus , Sandwich Island Climber (Antigonon and Plumbago )
7 . Crumbled - When the leaf is irregularly folded as in cabbage .