120 BRITISH GALLS 



swollen part. The peritheda are the flask-shaped bodies 

 containing the long needle-like spores. This fungus is widely 

 distributed in the south of England, and does much mischief 

 in some districts, where it attacks many pasture grasses. 



Protomyces macrospoms infests varioas umbelliferous plants, 

 giving rise to conditions well shown in Plate XXVII., 

 in which we see a large indurated swelling on the stalk 

 of the Hemlock Water Dropwort, and numerous swollen 

 seed-vessels. The tumefactions are at first pale yellow, 

 then pinkish, and finally brown. They contain the spores 

 which are formed in the continuit;y of the mycelial hyphae. 

 These galls may be found from May to October ; they are 

 very uncommon. 



There are some excellent photographs in Connold's " Oak 

 Galls " of the cankerous growths commonly seen on the 

 branches of young Oaks in many counties. They are 

 attributed to the fungus Dichaena quercina, but mycological 

 authorities agree that this is not at all likely, and the 

 cause of these tumours still awaits investigation. The 

 first indication is rounded swellings about the size of peas, 

 these coalesce and not infrequently girdle the stem. They 

 grow slowly, and in a few years become deeply fissured. 

 I have never observed a fungus upon these hypertrophies. 

 Connold also figured, in '• Plant Galls," roots of Amucaria 

 imhricata with large tumours, which he attributed to the 

 presence of Peridermium elatinum ; also similar growths on 

 Hazel, Sallow, etc. There is a considerable collection of 

 wood tumours in the Haslemere Museum on stems and 

 branches of Scots Pine, Cedar, Hazel, Elder, Holly, Larch, 

 Horse Chestnut, Beech, Birch, etc., and on roots of Scots 

 Pine and Vines, but in no instance is it possible to state with 

 confidence the primary cause of the overgrowth. It may 

 have resulted from mechanical injury to a bud, from insect 

 or fungus irritation, or from the presence of a bacterium. 



