242 PHYTOPHTHORA MEADII n. Sp. ON HEVEA BRASILIENSIS 



coloration and softening of the bark on the 12th day and 3 did not. The 

 cups were then removed. The spots gradually dried up and extension stopped. 

 Six weeks afterwards the spots were quite dried up and the bark below was 

 healtliy. The controls did not show any rotting, (c) During the monsoon 5 

 were inoculated but no flap of waxed cloth was used. None of them developed 

 rot. This may have been due to the fact that a very heavy downpour of rain 

 about an hour after inoculation may have washed out the infective material. 

 (d) A small piece of the dead bark of the tapped surface was peeled off exposing 

 the green layer and a plasticine cup moulded round and below it. The inocu- 

 lation was done exactly as before. Of 14 inoculated 10 showed discoloration 

 on the 7th day and 4 did not. The latter were re-inoculated as before on the 

 7th day. After 47 days 13 had bark-rot and one had not. In all cases the 

 controls showed no sign of rotting. The spots varied in size up to 5x5 

 centimetres and extended chiefly on the tapped surface, but sometimes down- 

 wards slightly into the untapped bark. The tissue was soft and rotten, in 

 some cases as deep as the cambium. It contained hyphae of Phjtophthora 

 which produced sporangia. Longitudinal cracks appeared in some of the 

 spots. Some months afterwards the trees were examined ; then all the spots 

 had healed and during the succeeding monsoon none of them renewed their 

 growth. 



(6) On the inflorescence. For each experiment a part of the branch with 

 an inflorescence was kept in water under a bell-jar. Six each were used for 

 the inoculation of the rachis, the peduncle, and the flower, and six were kept as 

 controls. Within 6 days the region round the inoculated place on the rachis 

 became discoloured and sections showed the presence of hyphse of PhjtophtJiora 

 within the tissues. The flowers fell from the inoculated peduncles which 

 shrank slightly and turned black and contained hyphffi within their tissues. 

 The inoculated flowers withered, became dark-coloured and fell off. Carefully 

 teased out flowers showed the presence of hyphae of Phytophthora within the 

 tissue of the perianth and ovary, and sporangia were present on some in con- 

 siderable numbers. Control inflorescences remained healthy and did not 

 become discoloured. 



(7) On the fruit. Clean-skinned fruits, about full size but with the skin 

 green and unsplit, were washed well in sterile water with sterile cloths, dried 

 with sterile cloths and placed in potato-dishes. Great care has to be exercised 

 in getting them clean, else moulds appear and vitiate the cultures. 



(ft) In each of 5 potato-dishes four fruits were placed. In one the fruits 

 were inoculated at the stalk-ends, in another at the flower-ends,, and in a third 



