Apical and intercalary meristems

Meristematic tissue is not scattered through the plant. It sits in particular places, and each place produces a particular kind of growth.

Figure to be added

Figure 1.4 — a grass-like plant with its meristems marked: the apical meristem at the very tip of the shoot, intercalary meristems at the bases of the internodes, and lateral meristem shown at A on the stem with a cross-section at B showing it as a ring inside the stem.

Apical meristems

Apical meristem

Found at the apex of the shoot and of the root, and in the axillary buds. Because of the activity of apical meristematic tissue, the plant increases in height.

Intercalary meristems

Intercalary meristem

Found at the bases of the internodes of the stem. Because of the activity of intercalary meristematic tissue, the internodes increase in length. Intercalary meristems are found in abundance in plants of the grass family.

Why grass survives being cut and mown

A plant that grew only from its tip would be finished the moment the tip was eaten or cut off. Grass grows from the bases of its internodes instead, which are low down and out of reach — so it regrows after grazing, after mowing and after a fire. A lawn works because of where its meristems sit.

Every meristem is named for where it is

Apical, at the apex. Intercalary, inserted between. Lateral, at the sides. The names are not new vocabulary to learn separately — they are the positions, and the kind of growth each produces follows from the position.