LASIODIPLODIA. 455 



If we collect the opinions of those mycologists who are 

 known to have examined this fungus, we find that seven have 

 considered it a simple Diplodia. three a Choitodiplodia, three a 

 Botryodiplodia , and six a Lasiodiplodia. If, however, we con- 

 sider only the independent determinations of the fungus, the 

 number of times it has been assigned to Lasiodiplodia is only 

 four, and in none of these four cases has the determination been 

 based on an examination of material in the country of origin. 



These differences of opinion cannot be attributed to any 

 fault on the part of the describers. Each classifies the fungus 

 according to the form he happens to have. On Hevea stems 

 and cacao branches it is usually a simple Diplodia, often 

 united into groups by a basal weft of hyphse ; as Howard 

 decided, one is scarcely justified in placing it anywhere but 

 in Diplodia on such material. On cacao and Hevea pods 

 it is either simple or grouped, and here it might sometimes be 

 assigned to Botryodiplodia, though there is no true stroma, 

 and the pycnidia are best described as subconfluent. Wlien 

 the pycnidia have developed on cacao pods in a satm'ated 

 atmosphere, they are distinctly pilose, and if scattered they 

 cannot be referred to any group but Chcetodiplodia. When 

 the fructification emerges from the points of origin of the 

 lateral roots of young Hevea plants, it is an undoubted 

 Botryodiplodia, with a glabrous solid stroma ; but under 

 exceptional conditions this stroma may be surrounded by 

 hyphse {fide Brick) , and it is then a Lasiodiplodia. ■ 



It is evident from this example that the present system of 

 subdivision of the genus Diplodia is, in part, based upon 

 characters wMch are not constant. The primary groups , viz. , 

 simple Diplodias and Diplodias united into a stroma, are not 

 mutually exclusive. A Botryodiplodia may form isolated 

 pycnidia and grouped subconfluent pycnidia as well as true 

 stroma ta. However, this division might stand, if it is 

 extended to mean that the first group includes those Diplodias 

 which never form a stroma, while the second includes 

 those which sometimes form a stroma and sometimes 

 scattered pycnidia. But under these circumstances , the correct 

 determination of a species would involve a more extensive 

 examination of material than is at present customary. 



