Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplants00tube Year: 1897 GYMNOSPORANGIUM. 387 may be as long as 10 and are bent like a horn (Fig. 219). A similar case is described by Barclay in which the peridia of aecidia on Rhamnus daliurica were very long if produced in dry weather, but short if in moist weather. The aecidiospores are shed during the early part of June, and germinate at once on the bark of young juniper-twigs; the mycelium growing thence into the
Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplants00tube Year: 1897 GYMNOSPORANGIUM. 387 may be as long as 10 and are bent like a horn (Fig. 219). A similar case is described by Barclay in which the peridia of aecidia on Rhamnus daliurica were very long if produced in dry weather, but short if in moist weather. The aecidiospores are shed during the early part of June, and germinate at once on the bark of young juniper-twigs; the mycelium growing thence into the spurs or branches to spread and hibernate, Teleutospores which germinate on Pomaceae other than species of Crataegns have apparently a normal mycelium, but produce pycnidia only, or aecidia with Fig. 220.—Cross-section through a swuUiiiy caused by Oi/.,<.,io,jo,angium on Juniper-stem ; parenchyma with large cells and thin walls is present in abnormal quantitj'. (After Woernle.) peridia differing from those on Crataegus. My own experiments on the quince and mountain ash regularly produce pycnidia only. Wakker summarizes the anatomical changes induced in deformed shoots of hawthorn as follows: cork, collenchyma, sclerenchyma, and chlorophyll are not formed, lignification of the cells of medullary rays no longer takes place, and there are few intercellular spaces. Interfascicular cambium is not formed, while activity of the intrafascicular cambium is suspended at an early period, so that the vessels remain incompletely developed. The epidermis is irregularly formed and liable to ru{)ture. All parenchymatous cells undergo enlargement in a radial direction. Starch is stored up in large quantity, and the formation of calcium oxalate is diminished. 1 ' On the life-history of Puccinia coronata var. ,' Tranx. Liimcau Soc, London, 1891. -This probably is the explanation of tlie long peridia obtained by Pcyritsch And described by Magnus (/feWcAe d. naturivis'
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