TREES AND SHRUBS 



III. PJSSTS OF Till': ORNAMENTAL SHRUBBERY. 



Barberry Cluster-cups, Au-idium Berberidis, is a disease which attacks 

 the Common Barberry. The cluster-cups are to be seen during the summer 

 on the leaves, peduncles and fruit. They are rather elongated and packed 

 closely side by side in sub-rotund or oval patches. The margin of the cups 

 is white and toothed, and the interior is rilled with chains of globose orange- 

 coloured spores. Some authorities consider this pest as one stage in the 

 life-history of the Wheat mildew. 



Barberry Leaf Mildew, Microsphceria Berberidis, is a common pest of 

 Berberis vulgaris, and resembles the Gooseberry Mildew in appearance. The 

 globose receptacles are surrounded by a circle of about ten appendages, each 

 beautifully forked in a dichotomous manner. Each receptacle encloses about 

 six asci, and each ascus contains G-8 sporidia. The mildew may be checked 

 by the application of sulphur. 



Ivy leaves are attacked by at least three species of Spot. Dotted about 

 in the discoloured patches are small receptacles enclosing thread-like sporules. 



Leaf Sooty Mould, Capnodium Footii, is a very common black mould 

 forming thin sooty spots on the leaves of many plants, and often to be seen 

 on Holly, Ivy and Cherry Laurel. The creeping mycelium consists of colour- 

 less or brownish threads, each divided into a chain of cells. The perithecia 

 or receptacles are erect and bristle-like, and fringed at the mouth. All sooty 

 leaves should be picked off and burned. 



Phillyrea Rust, Uredo PhiUyrece, is sometimes found on the leaves of 

 Mock Privet, and takes the form of round, yellow pustules filled with orange- 

 coloured uredospores, each with a thick hyaline outer coating. 



Rhododendron Galls are often to be seen on the leaves of Rhododendron. 



ferrugineum, and similar gall-like swellings are produced on Bay-Laurel. They 



are caused by a fungus, Exobasidiiuii Rhododendri. They vary in size from 



f in. to about f in., and are at first yellowish-green, becoming reddish later, 



and covered with a delicate bloom. The mycelium traverses the interior of 



the gall, and the " bloom " consists of the fungus fruit. The naked spores 



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