ROOT DISEASES 129 



weeds grow up and shelter it, the fungus extends to the whole 

 of the stem and branches thus kept moist. 



In the rootstocks of herbaceous plants, as in thick, soft bark, 

 the firm round strands of mycelium, buff-coloured without, 

 white within, penetrate the parenchyma in all directions. 



B. Rosellinia bunodes, B. et Br. 



This fungus is recorded as the cause of root disease of coffee » 

 pepper, and associated plants in Southern India, of hibiscus in 

 Ceylon, of coffee and associated plants in Porto Rico. In the 

 Lesser Antilles, South found it on CastiUoa and camphor from 

 Grenada, and on limes in Dominica. The present writer has seen 

 it on hibiscus in Grenada, on limes, hibiscus, acalypha and 

 several unidentified native shrubs in Dominica. In St. Vincent 

 a disease of arrowroot is caused by a Rosellinia with the general 

 characteristics of this species, and very probably identical with it, 

 in connection with which examples have been seen of attack on 

 banana, plantain, cassava, tannia, yam, corn, pigeon pea. Sea 

 Island cotton, coffee, and avocado. Sugar-cane and Guinea grass 

 are among the few economic plants which appear to show marked 

 resistance. 



There is no doubt that this list could be extended indefinitely. 

 The writer has not met with R. bunodes on cacao, but South 

 records an instance of its occurrence on young cacao plants 

 growing near diseased arrowroot. 



R. bunodes was originally described from Ceylon by Berkeley 

 and Broome. It is at the present time responsible, where proper 

 precautions have not been taken, for steady and serious losses 

 of lime trees on recently cleared estates in Dominica. Since 

 the species previously discussed is about equally abundant 

 there on the same host, the records made previous to 1915 

 regarding black root disease of limes cannot usually be referred 

 to one species as distinct from the other. 



Under the conditions prevalent in the uplands of Dominica 

 and Grenada the perithecia are formed very readily and in great 

 abundance on the surface of exposed roots, around the base of 

 the stem of infested trees, and on infested woody material lying 

 about in damp situations. 



They are easily distinguished by the coarse, more or less 

 pyramidal warts with which they are densely covered. In one 

 instance only a nearly smooth variety has been seen. The spores are 

 exuded from the perithecium in a narrow thread without much 

 cohesion, and lie in a clump on its summit. The writer has no 

 evidence to offer as to the method or possibilities of their dis- 

 persal, but they would be easily carried away by heavy rain. 



The conidial fructifications are of the same type as those of 



* According to an opinion recently given by Fetch on material from Porto Rico the W.Indian 

 species may be found to agree more closely with A', goliatk Speg. described from Brazil. The two 

 species are in any case very close and not certainly distinct. 



K 



