This is a photograph of the meristem of a plant. A meristem is tissue in the growing parts of plants that is made up of undifferentiated cells. The end of this part of the plant is made out of meristem tissue. AS the cells in the meristem divide, they push up the tip of the growing plant. There are two types of meristems. The apical meristems refer to growing the plant upwards and downwards and the lateral meristems refer to growing the plant to the sides.