4 BULLETIN 1286, U. S. DEPARTMENT OF AGRICULTURE 
Specimens of a leaf disease collected in 1912 by V. Cayla on 
cultivated Hevea at Para, Brazil, and sent to Griffon and Maublanc 
(8) were found to be attacked by the same fungus described earlier 
from Brazil by Hennings, Dothidella ulei. In addition to the 
Dothidella, these authors found also on the same leaves pycnidia 
and conidia, which they regarded as stages of the same fungus. 
The pycnidial or Aposphaeria stage of Hennings they thought was 
merely spermatial, whereas the conidial form was identified as a 
Scolecotrichum. The three types of fructification were figured in 
addition to brown hyphal masses in the leaf tissues which resembled 
chlamydospores. 
In June, 1913, V. Cayla (5) called attention to the probable 
identity of the disease from Para as determined by Griffon and 
Maublanc with that earlier collected from the upper Amazon by 
Ule and with that described in Dutch Guiana by Kuyper. The 
disease was considered mainly a nursery trouble and restricted to 
plants growing on poorly drained or otherwise unfavorable sites. 
In British Guiana the disease was first reported in July, 1913, by 
Bancroft (1), who also considered it a nursery trouble, since it 
"was not observed on the older plants in the field." The fungus 
was forwarded to Kew, where it was regarded as a new species and 
was named Passalora heveae Massee. A description of this species 
appears never to have been published. 
In a summary of the above-mentioned literature in 1914 Petch 
(15, 16) expressed the conviction that in view of the close agree- 
ment of the descriptions of the fungi and the fact that the genus 
Passalora is doubtfully distinct from Fusicladium the disease in 
British Guiana should be considered identical with that in Dutch 
Guiana and Brazil. More recently (1915-1917) this relationship 
was definitely established and our knowledge of the disease and its 
effects greatly extended, as a result of a detailed investigation of 
the whole problem by Stahel (21, 22, 23) in Dutch Guiana. By 
careful comparison of material from Trinidad, British Guiana, and 
Dutch Guiana with collections and type specimens of the Dothidella 
from the upper Amazon, originally described by Hennings, Stahel 
was able to show beyond reasonable doubt that the fungus is the 
same in these different regions. He was unable to agree, however, 
that the perfect stage should be considered a Dothidella or even a 
member of the family Dothidiacese, but believed it more closely re- 
lated to the sphaeriaceous genus Melanopsamma, from which it 
differed sufficiently to require the erection of a new genus, Melanop- 
sammopsis. The latest name for the fungus is, therefore, Melanop- 
sammopsis ulei (P. Hennings) Stahel. The detailed results of this 
important work, which is published in the Dutch language and 
unfortunately not generally accessible, have been repeatedly drawn 
upon for much of the experimental evidence cited in this report. 
In June, 1916, Bancroft (2) published more fully on his observa- 
tions of the disease in British Guiana. Its origin in the colony was 
unknown; but the evidence pointed toward infection from the wild 
Heveas, of which at least two species had been observed to suffer from 
the trouble in the forest, Hevea confusa and an undetermined species. 
The disease occurred in all parts of the country but was less common 
on or near the coast lands. It was also most prevalent where large 
areas of pure Hevea were being grown. 
