506 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mildew, by dusting, spraying, etc., to see if any remedy could be used 

 that would take the place of tipping, i.e. cutting off the succulent shoots 

 which became so readily diseased. The results were not favourable to 

 any new method of treatment. Spraying twice in early spring with 

 lime, sulphur, or Bordeaux mixture, checks the disease to some extent, 

 but does not repay the cost of application. All forms of soil-treatment 

 and winter spraying tried appeared to be of no avail in checking the 

 disease during the following season. Heavy farmyard-manuring favours 

 the disease by encouraging the growth of succulent shoots. Tipping the 

 shoots is therefore the most effective means yet devised of reducing the 

 amount of disease, and should be done in autumn, the early part of 

 September being the most favourable period. Diseased fruits should be 

 destroyed as soon as they are noticed. 



F. Petch * has compiled a summary of the fungus diseases to which 

 Hevea brasiliensis is liable in Ceylon. Hevea has been grown under 

 very close supervision, and it has not been found that diseases have in- 

 creased, and, also, the majority of those diagnosed have not proved 

 serious ; one of the worst, indeed, Fomes semitostus, is now of minor 

 importance, seeing that the stumps which kept it going are being all 

 weeded out. Petch has divided them into leaf-, stem-, root-diseases, 

 etc., and he gives ample consideration to each group. He winds up with 

 an account of canker, due to Phytophthora Faberi, which attacks every 

 part of the tree except the leaves. Advice is given as to the most 

 practical way of treating disease. 



Lichens. 



(By A. Lobeain Smith, F.L.S.) 



New Lichens. f — A. Hue has described a series of lichens that have 

 been collected at various times. There is a new genus, Nylancleridella, 

 the second genus of the family Pyrenothamniaceae, distinguished by the 

 radiate character of the thallus, with perithecial fruits. The unique 

 species was collected in New Zealand in 1886. He gives a detailed de- 

 scription of Parmelia tristis, which he places in the genus Cetraria. He 

 makes a number of new species from forms that had been included 

 wrongly in existing species. 



* International Rubber Congress, etc., Batavia (1914) 16 pp. 

 t Ann. Mycol., xii. (1914) pp. 509-36. 



