a: Meristematic cells of the haustorium of Alectra vogelii, tropical scrophulariaceae: The meristematic cells are rich in plasma, the nucleus (with a dark nucleolus) fills a large portion of the cell's volume. The vacuole is not fully developed, intercellular spaces (v) are of a small volume if present at all. (R. KOLLMANN, 1977).
b: Parenchymatic cells from a vascular bundle of a parasitic species (Orobanche fuliginosa). The vacuoles of both cells shown in the picture are very large. The peripheral nuclei need only little space. The intercellular spaces are marked by triangles. (I. DÖRR, 1970)