Introduction to Fungi, Third Edition

CONTROL OF POWDERY MILDEW DISEASES
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Fig13.14 Phyllactinia guttata. (a) Chasmothecium on lower side of hazel (Corylus) leaf.The radiating bulbous appendages are
horizontal.The branched secretory appendages which crown the chasmothecium are on the morphologically upper side, i.e. the
side to which the ascus apices point. (b) Position of chasmothecium during its fall from the host leaf.The bulbous appendages are now
folded to form flight vanes, ensuring that the sticky mass of mucilage faces downwards. (c) Diagrammatic representation of an open
chasmothecium.The chasmothecium is shown attachedby mucilage to a surface.The chasmothecium has openedby a circumscissile
line of weakness, and has hinged back so that the apices of the asci now point outwards. Arrows indicate the direction of ascospore
discharge. (d) A bulbous appendage, showing the differential thickening of the wall of the bulb.Collapse of the thinner walls result
in movement of the appendage. (e) Two-spored ascus. (f) Branched secretory appendage. (a,b) to same scale; (d f) to same scale.