Hypocotyl

Hypocotyl (Greek: hypo = below and kotyle = cavity; engl: hypocotyl. ) Is a technical term in botany and refers to the lowermost portion of the stem axis of a seed plant from the root collar (which is the boundary zone between root and shoot axis) up to the cotyledons ( seed leaves ).

The next higher section of the stem axis between cotyledons and the primary leaf and the primary leaves, the epicotyl.

Thickening of the hypocotyl

In a thickened hypocotyl one speaks of a Hypokotylknolle which serves as other tubers of storage of reserve substances. Examples of types are radishes or beetroot.

• Plant morphology