Vascular tissue is not surprising that their form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the sections of a pipe might be. As the plant grows, new vascular tissue differentiates in the growing tips of the plant. The new tissue is aligned with existing vascular tissue, maintaining its connection throughout the plant. The vascular tissue in plants is arranged in long, discrete strands called vascular bundles. These bundles include both xylem and phloem, as well as supporting and protective cells. In stems and roots, the xylem typically lies closer to the interior of the
Coccus hesperidum all the nutrients they need, the scale insects ingest large quantities of sap. They then secrete the excess sugary fluid as honeydew. This is attractive to ants which often tend the scale insects, driving away predators. The brown soft scale does not normally kill the host plant, but the loss of sap probably causes it to grow more slowly and crop less heavily. The main disadvantage to the host is the sooty mould which grows on the honeydew. This reduces the area of leaf available for photosynthesis, and spoils the appearance of the plant, its flowers and fruits. Traditionally, brown