THE MONTHLY BULLETIN. 



279 



reddish-brown color (Fig. 84). The pycnospores are the first to appear. They are 

 formed in small yellow to orange-colored pustules (pycnia) from which they ooze 

 out in the shape of thin, irregularly twisted 

 coils or strings, each consisting of a 

 great number of spores. Later, usually 

 towards fall or winter, the second type of 

 pustules (perithecia) appears These are 

 orange to reddish-brown, and contain great 

 numbers of small sacs, each of which 

 produces in its interior eight ascospores. 

 Upon maturity the ascospores are ejected 

 with some force from the pustules, but do 

 not come out in strings as do the pycno- 

 spores. 



Both spore forms may continue to be 

 produced long after death of the affected 

 part and both are able to infect sound 

 chestnut bark. 



As far as known only chestnuts and 

 immediate relatives are known to be sub- 

 ject to the disease. The introduction of the 

 fungus into California would spell death 

 to all chestnuts. At present the chestnut 

 industry of the Pacific coast can not be 

 called important, but there can hardly be 

 any doubt that with the disappearance of 

 the eastern tree the cultivation of chestnut 

 on the Pacific coast will be strongly stimu- 

 lated. Raising chestnuts for consumption 

 is far too profitable a business not to be 

 tried in a climate so eminently suited to 

 this industry. If the chestnut bark disease 

 is permitted to reach the Pacific coast the 

 future of this branch of horticulture will 

 be doomed. 



There is strong evidence that some oaks, 

 in particular tanbark oak, are not immune. 

 The danger to the tanbark oak industry of 

 California from the introduction of the fun- 

 gus is obvious. So far it appears that the 

 giant chinquapin (Castanopsis chryso- 

 phylla), a very close relative of chestnut. 

 is not subject to the disease. As long as 

 this is not proved beyond the shadow of a 

 doubt, the fungus must be regarded as a 

 potential enemy of this magnificent tree. 

 This chinquapin occasionally reaches six 

 feet in diameter and up to 115 feet in 

 height, and produces excellent saw lumber 

 in a country exceedingly poor in valuable 

 hardwoods. 



The state of California has every reason 

 by all means at its disposal to prevent the 

 introduction of one of the most yirulent 

 and destructive fungi known to plant 

 pathology. 



Fig. 84. — Chestnut stem with typi- 

 cal canker of chestnut bark disease. 

 The concentrical advance of the fun- 

 gus in the bark is marked with chalk. 

 The older portions of the canker to the 

 right are thickly covered with small 

 pustules (pycnia and perithecia). 



