. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. THE PARASITIC EXOASCEAE. 159 duciiig the brooms by artificial infection of alder. The disease is common and epidemic, and a single tree may carry as many as a hundred brooms. The witches' brooms are composed of many thickened twigs, beset with an abnor- mal number of lenticels, and the point of infection shows a distinct swelling, from which the broom tends to turn directly upwards. The leaves are somewhat modified, t
. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. THE PARASITIC EXOASCEAE. 159 duciiig the brooms by artificial infection of alder. The disease is common and epidemic, and a single tree may carry as many as a hundred brooms. The witches' brooms are composed of many thickened twigs, beset with an abnor- mal number of lenticels, and the point of infection shows a distinct swelling, from which the broom tends to turn directly upwards. The leaves are somewhat modified, they are larger and thicker than the normal, they unfold later and wither earlier, while their stipules remain attached for some time. The brooms of alder only survive a few years, and by their decay cause the death of large branches, and frequently of the whole tree. The asci, which are sunk in a depression of tlieir stalk-cell, form a white coating on both surfaces of the leaves. The mycelium hil)ernates in the l:)uds. Exoascus turgidus Sad. causes- the formation of witches' brooms on Bdvla verrucosa. The leaves form- ed on the brooms are some- what crumpled, and the asci are produced on their lower surface. Exoascus betulinus Eostr. produces witches' brooms on Bdula puhescais and B. epiphytlits. broom in first year, shovving swelling at the point of infec- tion. The leaves are already shed in autumn, while the normal still remain 4 natural .size. After V. Tubeiif.). 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 Tubeuf, Karl, freiherr von, 1862-; Smith, William G. London, New York [etc. ] Longmans, Green & co.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherl, booksubjectfungi
