. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PLASMODIOPHORA. 525 decay, so that not only is the root itself worthless, but the aerial shoot is badly developed. The destruction is greatly favoured by moist rainy years. The malformations of the root are the result of hypertrophy of the host-cells due to a stimulus exerted by the plasmodium of Plasmodiophora, not only on the contents of cells inhabited by it, but also extending into the cells of the whole neigh- bouring tissue. The cells so influenced enlarge in size and. Fig. 315.—Plasmodiophora brassicae. Effects on Turnips grown in Scotland, (v. Tubenf phot.) become divided up by new cell-walls. The plasmodium makes its way from cell to cell by means of the wall-pits, and by absorbing the contents it grows and fills the whole cell. On exhaustion of food, and without previous enclosure in a membrane, the plasmodium forms itself into spores, so that the tissues of attacked roots become completely filled with thick- walled spores, which are set free only after decay of the surrounding tissues and cell-membranes. The spores hibernate, and in spring myxamoebae slip out, capable of infecting. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Tubeuf, Karl, freiherr von, 1862-1941; Smith, William G. London ; New York [etc. ] : Longmans, Green & co.