MELANCONIUM 433 



centre of the patch is usually darker in colour and brown, the 

 remainder studded with the minute, black perithecia. 



Spores fusiform, ends acute, i-septate, hyaline, 15-16 X 



3-4 P- 



This fungus sometimes proves very destructive to cultivated 



cabbages of various kinds. 



Ascochyta armoraciae (Fckl.) forms spots on the leaves of 

 horse-radish. Conidia elliptic, oblong, i-septate, 18-20X3 /x. 



Ascochyta aquilegiae (Roum.) forms rounded, whitish spots 

 with a dark margin, on columbine leaves. Conidia narrowly 

 elliptical, tinged brown, i-septate. 



MELANCONIACEAE 



** Spores continuous 



MELANCONIUM (Fr.) 



Spore-masses produced in the substance of the host, usually 

 in the cortex ; conidia elliptical, olive, extruded as blackish, 

 mucilaginous tendrils. 



Screw-pine disease. Specimens of screw-pine {Pandanus) 

 grown in this country are not infrequently attacked by a 

 disease which kills the branches, or in some instances the 

 entire plant, as happened at Kew some years ago to a very 

 fine plant. Melanconium pandani (Lev.), the cause of this 

 disease, forms black pustules embedded in the bark, from 

 which ooze to the surface black, subgelatinous tendrils, con- 

 sisting of minute conidia embedded in mucilage. These 

 tendrils are usually produced in such profusion that the 

 branch is completely blackened. 



I have been told that mangrove-trees, when growing in 

 their native habitat, are often killed by a disease which gives 

 them a blackened appearance as if they had been scorched. 

 This disease is probably caused by the same Melanconium. 



An ascigerous fungus, Nectria pandani (Tul.), frequently 

 appears on the old and empty Melanconium pustules, and the 

 two have been considered as phases of the same fungus. 

 This supposed connection, however, has not been proved, and 

 it is rather outside experience to suppose there can be any 

 relationship. 



Fruit erumpent, large, black, conoid, often grouped in 



2 E 



