Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 1G6 ASCOMYCKTES. This is supported l)y Smith's investigations, in which an an- atomical comparison of diseased twigs of peach and ahiiond showed no difference in the patliological effects. Exoascus crataegi Fuck, occurs on Crataef/us Oxyacantha, and causes red swellings on the leaves and flowers, accom- panied by hypertrophy of shoots in which the mycelium perennates. Exoascus Tosquinetii (West.), The
Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 1G6 ASCOMYCKTES. This is supported l)y Smith's investigations, in which an an- atomical comparison of diseased twigs of peach and ahiiond showed no difference in the patliological effects. Exoascus crataegi Fuck, occurs on Crataef/us Oxyacantha, and causes red swellings on the leaves and flowers, accom- panied by hypertrophy of shoots in which the mycelium perennates. Exoascus Tosquinetii (West.), The deformation caused by this species is freijuent on the black alder {Alaus gliitinosa). The thickened, elongated, wrinkled twigs render attacked parts very conspicuous in contrast to the normally developed parts of the tree. The leaves may l)e wholly attacked and much enlarged, or they may only be hypertrophied at places so as to form pustule-like swell- ings. The epidermal and mesophyll-cells of diseased leaves become greatly en- larged. Exoascus aureus (Pers.). The leaves of the lilack poplar {Pdjni/us 'iiif/ra) attacked by this parasite exhibit pustules (Fig. 62). The asci are formed as a golden coating on the concave side of the pustules, which is, in most cases, the under side of the leaf, rarely the upper. The cells forming the pustules have thicker walls and a somewhat different shape from the normal epidermal cells, and they are not unfrequently sub-divided by walls of secondary origin (Fig. 63). According to Smith, the cells of the palisade parenchyma have also thickened walls, as well as being elongated and occasionally chambered ; the cells of the spongy parenchyma are enlarged and have thicker walls; so also are the cells of the collenchyma of' the leaf venation. Fici. 0-.—Exoascus Leaf of nUjra, showing the p\istule-like swellings. Tubeuf del.) (V.
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