Question

Imparipinnate leaf is the one where
A. Leaflets are borne in pairs
B. Leaflets are small
C. Leaflets are large
D. Rachis is terminated by an odd leaflet

Answer 1

Hint: A leaf is usually a lateral and generally flattened structure that is borne on the stem. It develops at the node and bears a bud in its axil. It originates from the shoot apical meristem and arranged in an acropetal order of the stem. Leaves are the most important and only vegetative organ for photosynthesis.

Complete answer: The leaf in which the lamina or leaf blade is completely broken into distinct leaflets is called compound leaf. The leaf has incisions which reach the midrib. Compound leaf contains a bud at the axil of the petiole but is absent in the axil of leaflets. The compound leaves are of two types: pinnately compound and palmately compound. Imparipinnate leaf is a type of pinnately compound leaf.
Leaflets are borne in pairs: when this condition happens it is called a paripinnate or even pinnate leaf. It is a type of compound leaf.
Leaflets are small: When leaflets are small it is called a palmately compound leaf. The leaflets remain attached to a common point. It is usually seen in silk cotton.
Leaflets are large : it is a type of simple leaf . The leaf blade is not divided and if incised the incision does not touch the midrib.
Rachis is terminated by an odd leaflet: it has a lone pair of leaflet and not the terminal pair of leaflet thus has an odd leaflet and not even. It is seen in Neem.

Our required answer is d Rachis is terminated by an odd leaflet.

Note: Some types of pinnate leaves are:
Tripinnate: Secondary axis produces tertiary axis which bear leaflets e.g., Moringa, Melia.
Decompound: Rachis is divided repeatedly without any definite pattern so that the lamina is dissected into narrow segments e.g., Carrot, Parthenium, Coriandrum. attached to a common.