Diseases of plants induced by Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith diseasesofplants00tubeuoft Year: 1897 THK PARASITIC' KXOASCEAE. \b'J duciujj; the brooms by artificial iiit'eetiou oi' alder. Tlie 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 ten
Diseases of plants induced by Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith diseasesofplants00tubeuoft Year: 1897 THK PARASITIC' KXOASCEAE. \b'J duciujj; the brooms by artificial iiit'eetiou oi' alder. Tlie 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 uiwards. 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 their stalk-cell, form a white coating on both surfaces of the leaves. The mycelium hibernates in the buds. Exoascus turgidus Sad. causes the iuriiuiliun oi witches' brooms on Bctnln verrucosa. The leaves form- ed on the lirooms are some- what crumpled, and the asoi are produced on their lower surl'acL-. Exoascus betulinus liostr. produces witches' blooms (jU llilnlii i)iihisi'ini< and /A othirntu. Flijilii/lliit. Witches' brunni in first yuur, showiiiK HWelliii); iit tho jmiiit <i( liifii-- tiiiii. The IcuvcM luo uhi'uily whcil In iiutuinii, whtlo thu iiorinal »tlll rfinitiii J iiiitiiril xWv. After V. TiiJaMif.)
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