Compound leaves and phyllotaxy

Simple leaf: the lamina is entire, or its incisions stop short of the midrib.

Compound leaf: the incisions go all the way to the midrib and split the lamina into separate leaflets.

A bud sits in the axil of the petiole of both simple and compound leaves, but never in the axil of a leaflet. This is how a leaflet is told apart from a whole leaf.

Pinnately compound: many leaflets on one common axis, the rachis, which stands for the midrib. Example: neem.

Palmately compound: all the leaflets are attached at one point, the tip of the petiole. Example: silk cotton.

Phyllotaxy is the pattern in which leaves are arranged on a stem or branch. There are three usual types.

Alternate: one leaf at each node, placed alternately, as in china rose, mustard and sunflower.

Opposite: two leaves at each node, facing each other, as in Calotropis and guava.

Whorled: more than two leaves at a node, forming a ring, as in Alstonia.