271 



produced in rapid succession from the tips of the sporophores, 

 and soon fill the cavity of the fruiting body, which now begins 

 to indicate its position by a slight wart-like protuberance under 

 the epidermis of the host plant. When the fruiting body of the 

 fungus is replete with spores, the sporophores deliquesce and 

 form a highly hygroscopic substance, which increases very 

 considerably in volume when in contact with water. This 

 peculiar property of the disintegrated sporophore-material enables 

 the spores to escape from the fruiting body into the air. 



When the spores are mature and the sporophores have deliqu- 

 esced; the whole are extruded from the fruit through a rupture in 

 the epidermis caused by the increasing pressure of the spore- 

 mass. This extrusion takes the form of tendrils, consisting of 

 myriads of spores immersed in mucilage, and takes place after 

 a shower of rain, the water causing the mucilage to swell to a 

 remarkable extent. At the moment of extrusion these tendril- 

 like bodies are very soft and gelatinous, but they commence to dry 

 and harden the moment they come intc contact with the air, and in 

 the act of drying usually become spirally coiled and variously 

 contorted. The extrusion of the entire mass contained in a spore- 

 cavity usually occupies about five minutes. In dry weather the 

 teodrils are rigid and horny, but they become soft and glairy 

 when moistened with rain or dew. These spore-masses are not 

 dispersed by wind, but depend for their dissemination to a great 

 extent on birds, who convey the spores when moist and gelatinous 

 from diseased to healthy shoots by means of their feet. 



The shoots are only capable of infection while quite young, but 

 when the mycelium has gained an entrance into the tissues it 

 spreads rapidly and infects the entire growth of the season. _ Four 

 shoots infected respectively at one point only, when three inches 

 long, and protected from the visits of birds by netting until the 

 end of the year, were found the following year to be infected 

 throughout their entire length— about J 5 inches— and produced 

 numerous tendril-like masses of spores. In another experiment 

 a branch bearing six shoots was selected ; three of the shoots 

 were infected with spores, whilst the remaining three were lett 

 uninfected as controls. All these shoots were protected by 

 netting, and the following year the three infected shoots were 

 badly diseased, while the uninfected control shoots remained 

 healthy. No success attended the many attempts to mtect 

 branches more than one year old, not even when spores were 

 placed in a wound made in the cortex. 



The spores do not retain their power of germination for more 

 than about three months. 



Description of the Figures. 



1. A two-year-old shoot showing the first symptoms of disease. Nat. size. 



2. A dead shoot showing the tendrils of spores. Nat. size. 



3. Section of cortex of a diseased shoot, showing spore-conceptacles and 

 tendrils of spores. Slightly mag. 



«*^uriis oi spores, e>iijrnuy mag. 



4. Portion of a tendril showing the spores imbedded in mucus, Mag. 

 B- Spores, some germinating. Highly map:. 



32998 



A2 



