Coleus apex detail LS
This longitudinal section of the apex shows
several regions, which contain compact (darkly-stained) meristematic areas. The shoot apex proper, lies between two
developing leaf primordia at the top, and the bumps and projections which
occur down the flanks, represent zones where leaf primordia have been formed
Two axillary meristems can be seen in this micrograph. These will produce lateral branches once the meristematic tissue is far enough away from the influence of the shoot apical meristem. Hormone gradients, particularly an auxin gradient produced by the apex, will suppress their growth.