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AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
attempt to clothe superficial systematic work in the garb of respectability by 
assuming host delimitation for forms belonging to groups in which no clear 
case for such delimitation has been made out. Morphologically indis- 
tinguishable fungi not known to be confined to particular hosts are best 
called by the same name. It is idle, for example, to use one name for the 
Pestalozzia strains causing the gray blight of tea and another for those 
which cause leaf spot of palms. In both cases, as we have found, the 
strains show differences among themselves, covering a wide range of varia- 
tion, just as do the strains from Hevea. Our isolations from hosts other 
than Para rubber were made in order to find out whether or not the strains 
infecting these hosts were distinct, and, providing they were, whether or 
not they had served as sources of infection for Hevea. 
Of all the common hosts of Pestalozzia in the East Indies, it seemed 
least likely that Hevea would be found to be infected with specifically 
restricted strains. In fact, it appears that all the common diseases of 
Para rubber in the Orient are due to more or less ubiquitous fungi, and that 
no serious, specific diseases of Hevea were introduced from Brazil with 
the original rubber seed. It is accepted by Burkill (3), who has gone over 
the existing records with care, that all the oriental Hevea has descended from 
a single introduction of seeds collected for the Government of British India 
on the upland plateaus near the valley of the Tapajos River in Brazil. 
The seeds were grown at Kew, the latter institution having served the 
purpose of the modern quarantine station, for no diseased stock seemed to 
have been forwarded to Ceylon and Malaya. In consequence, the causes 
of rubber diseases in the East are found among those fungi which are little 
restricted as to host. Generally speaking, the forms pathogenic to Hevea 
have been reported as causing diseases of the most diverse cultivated plants. 
In view of thes,e facts it was natural that we should attempt to identify 
the Pestalozzia strains of Hevea with those of other plants from which these 
fungi have been described or reported. As with so many other genera of 
Fungi Imperfecti, the descriptions of the nominal species of Pestalozzia 
are generally in no degree diagnostic. There are whole groups of descrip- 
tions of which nothing whatever is left, when common factors are canceled, 
except the names of different host plants and different geographic localities. 
Quantitative data, when given, are seldom, if ever, stated so that one is 
convinced of their accuracy. 
Pestalozzia is chiefly known in the eastern tropics through causing the 
gray blight of tea and the leaf spot of the cocoanut palm. The literature 
shows that several specific names have been applied to the causal fungi 
with only the vaguest notions of specific delimitations in the group. Of 
these names the oldest is Pestalozzia Guepini Desm. (first published by 
Desmazieres (4) as Pestalotia Guepini). It was originally applied to a 
form or forms from Camellia and Magnolia, characterized by a spore 
length of about one fiftieth millimeter, with four-septate spores, the terminal 
