Pflanzenkrankheiten. 213 



phytic according to circumstances. In all probability both conidia 

 and ascospores are equally effective in spreading the disease. 

 A detailed specification of Sphaerostübe repens is appended. 



W. E. Brenchley. 



Petch, T., Brown Root disease {Hynienochoete noxia, Berk.). 

 (Circ. Agric. Journ. xoy. bot. Gard. Ceylon. V. 6. p. 47—54. 1910.) 



This is a very common root disease of Hevea in Ce^'lon, and 

 it also attacks many other species. The leaves of injected plants 

 wither and fall off, and the tree dies. The roots are curiously en- 

 crusted with a mass of sand and stones, which are cemented to 

 them by the brown threadlike mycelium of the fungus. The cortex 

 of the root is decayed, and if the wood is affected it is usually 

 yellow. Sometimes a honey comb like structure is developed, con- 

 sisting of ordinary wood cells filled with "wound gum". The fructi- 

 fication forms a thin dark brown crust adhering to the base of the 

 stem. The patch appears finely velvety, being covered with minute 

 projecting bristles, which are characteristic of Hyinenochoete. 



The ordinary means of infection is by the gradual spread of 

 mycelium along the roots to the roots of adjacent bushes which are 

 in contact, the rate of progress under favorable conditions being 

 very slow. All dead trees should be dug out and burned. 



A description is also give of a similar disease caused by Hyme- 

 nochoete rigidida, B. & C, in which the honey comb structure of 

 diseased wood is well developed. An account of the occurrence of 

 H. noxia in other countries is appended. W. E. Brenchley. 



Petch, T., Root diseases of Acacia decurrens. (Circ. Agric. Journ. 

 roy. bot. Gard. Ceylon. V. 10. p. 89—94. 1910.) 



Two diseases are common — one caused by an Agaric Armil- 

 laria fiiscipes, which is generally distributed, and one due to ivjw^s 

 australis, only found in the ßotanic Garden at Hakgala. 



Armillaria fiiscipes, Petch. 



Mycelium occurs in red and white sheets between the bark and 

 wood of the root, and possesses a strong "mushroom" smell. The 

 fructifications arise in Clusters of six or more from a greyish swollen 

 cushion in the stem, the cap being brown with the margin turned 

 upwards. Enormous quantities of tiny white spores are produced. 

 The disease is spread primarily by spores, and ultimately by 

 rhizomorphs, Strands of mycelium which penetrate the soil. 



Fontes australis. 



Usually saprophytic, sometimes a wound parasite, but s^xy 

 slow in action. The sporophore (fructification) first as a white cork}'- 

 nodule, which developes into a spreading horizontal bracket, may be 

 2 feet broad, wich a vertical margin sometimes two inches deep, 

 most of the sporophore consists of a layer of vertical tubers in which 

 the spores are produced. The fructification is perennial, and may 

 persist for three or four years, After a time the bark of the affected 

 tree falls away and reveals white patches of mycelium between the 

 wood and bark. The wood itself is attacked eventually. 



Probably the fungus is spread along the roots of one tree to 

 the next, where the roots are in contact. W. E. Brenchley. 



