120 FUNGOID PESTS OF CULTIVATED PLANTS. 



Apple-bark Valsa. 

 Valsa ambicns (Fr.), PI. X. fig. 7. 



It is only during the past year or two that we have become satisfied 

 that this usually saprophytic fungus has seriously affected living Apple 

 trees — at least during its early or conidial condition. 



The bark of living branches and trunks was observed to be roughened 

 with little elevations from the apex of which proceeded what appeared to 

 be a long twisted yellow filament, not thicker than a horse-hair, entangled 

 together into a mass of golden threads. When moistened these threads 

 dissolved into myriads of minute curved conidia (5 /.i long) which had 

 oozed out from minute punctures of the bark, and proved to be those of a 

 fungus called Cytospora carphosperma, common on many orchard trees, 

 but heretofore considered saprophytic. 



The mature condition is to be found in spring on branches that have 

 lain on the ground through the winter, and consists of clusters of 

 receptacles, flask-shaped, with long converging necks, containing sporidia 

 which are cylindrical, curved, and rounded at the ends (16-18 x 3-4 /j), 

 and of these eight are produced together in a membranous sac or ascus. 

 This mature condition is only arrived at after hibernation, and con- 

 sequently upon dead branches, but the early stage is clearly parasitic and 

 may become troublesome. The mature stage is called Valsa ambicns. 



Certainly whenever seen oozing out of living trees the parts should 

 be well rinsed with Bordeaux mixture, so as to destroy all the germinating 

 power of the conidia. 



Sacc. Syll. i. 512 ; Cooke Hdbh. No. 2475 ; Curr. Linn. Trans, xxii. 

 t. 48, f. 138. 



Apple-tree Hydnum. 



Hydmim Schiedermayeri. 



Very recently this large fleshy fungus has been developed on an old 

 Apple tree at Maldon, Essex, bursting through the bark in a long strip, 

 extending for 3 or 4 feet in an irregular mass. It has a nodulose 

 appearance, of an ochrey-yellow or flesh-colour. The nodules produce 

 long spines, which are covered by the hymenium producing the spores. 

 According to Thiimen, this fungus is very frequently destructive to 

 Apple trees, and is presumably a wound-fungus, the spores entering 

 through a wound or fissure of the bark, and soon becoming developed. 



Gard. Chron. Oct. 31, 1903, p. 299 ; Mass. PL Dis. fig. 39. 



Pear-leaf Cluster-cuts. 

 Iimstelia cancellata (Reb.), PL X. fig. 8. 



There is hardly any parasite which appears to be such a puzzle to 

 gardeners as the Boestelia or " cluster- cups " of the Pear leaves. They 

 have also been a puzzle to others who are not gardeners, as evidenced 

 by the literature of the past quarter of a century. We can permit the 

 discussion to rest and state a few conclusions. 



The parasite thickens the Pear leaves at the infected spots by the 

 internal growth of the mycelium upon this, and externally are produced 



