282 
Journal of Agricultural Research 
Vol. XXV, No. 6 
DISCUSSION 
RELATIONSHIP 
The two strains of Phytophthora are, therefore, to be considered as 
identical. Both behave alike in infection experiments. The physio¬ 
logical characteristics of each from a standpoint of growth on various 
media, relation to light, relation to temperature, and relation to acidity 
and alkalinity are the same. The morphological characteristics are also 
so nearly alike that no real distinction can be made between them. 
Both strains of the fungus correspond closely to the Faberi group and to 
the species Phytophthora faberi Maubl. as determined by Rosenbaum (8). 
Antheridia are entirely unknown. The papillae of the conidia are raised 
and very prominent. The measurements of conidia and chlamydo- 
spores closely approximate those for this species.. There is a slight 
variation in the ratio of the length to the width of conidia. This differ¬ 
ence, when taken into con¬ 
sideration with all the other 
points of similarity, is not 
sufficient to warrant the cre¬ 
ation of a new species. Ro¬ 
senbaum (8) gives i .47 as the 
mean ratio of length to width 
of conidia of Phytophthora 
faberi Maubl. The ratio ob¬ 
tained in the last compara¬ 
tive measurements for both 
strains on oatmeal agar was 
i.6o. Measurements made in 
1919 (7) of the coconut strain 
grown on com meal gave 
a mean ratio of 1.51, being 
more nearly that as given 
by Rosenbaum. The slight 
change in the form of the 
spores measured in 1919 and 
1922 can not be accounted 
for unless it be due to a difference in age and a change in the medium used. 
The original description of Phytophthora faberi Maubl. as given by 
Maublanc (4) in 1909 on cacao (Theobroma cacao) corresponds also very 
closely to that of the two strains studied by the writer. 
In 1907 Butler (2) described a new species of a Phycomycete occurring 
on various hosts, among which was the coconut (Cocos nucifera), under 
the name of Pythium palmivorum. Later in 1918 (3), the genus was 
transferred to that of Phytophthora without redescription. In 1907 
Ashby (j), in an article on two diseases of coconut palm in Jamaica, 
ascribed the cause of the budrot to Phytophthora palmivorum Butl. 
after having submitted a culture to Butler for comparison. A 
culture of the fungus from Jamaica (Ashby, subculture of 31-8-20), 
obtained from Mr. A, Sharpies, mycologist of the Federated Malay 
States, appears to be very much like that of the Phytophthora on coco¬ 
nut and cacao from the Philippines. No accurate comparisons, however, 
were made. The Phytophthora from the Philippines in all probability 
is different from that in India, as originally described under Pythium 
Fig. 5.—Graph showing the variation in the diameter of 
chlamydospores. 
