40 BTJLLEITN 934, U. S. DEPARTMENT OF AGRICULTURE. 
hyphae which bear them. Both oogones and chlamydospores may be 
either terminal or intercalary. 
The normal hyphae are large, varying from 3 to 7 pi and sometimes 
more in diameter. Typical hyphae, showing the false septa developed 
at the boundary of the protoplasm and the portions of the hyphae 
which have been evacuated in the extension of the younger parts, are 
shown in Plate I. figure 1. At points at which the ends of hyphae come 
in contact with the glass of the culture dish, peculiar contact swell- 
ings are produced (PL I, figs. 5 to 7). much the shape and size of 
antheridia. but not walled off from the adjacent hyphae and having 
no apparent significance in the life history of the fungus. These are 
not always terminal (PL I. fig. 8). It is noteworthy that Hesse de- 
scribed contact swellings at the tips of the hyphae just before pene- 
trating the epidermis of CameUna sativa. 
The asexual nonsporangial fruiting bodies of Pythium debaryanum 
are referred to as chlamydospores rather than as conidia, though in 
most of the previous literature the latter term has been used for 
them. Hesse called the terminal bodies coniclia and the intercalary, 
gemmae (74). It is believed that the best terminology and the one 
which should be followed for all fungi, as it now is for most, is that 
which limits the term conidium to a spore which is adapted primarily 
for aerial distribution or which is at least readily separated as soon 
as it is mature from the parent hypha from which it arises. The 
most typical conidium. in fact, is a spore which is abstricted by the 
parent hypha at maturity. The asexual spores of this Pythium re- 
main attached to the parent hyphae indefinitely even after the hyphae 
are dead and empty. It is a common thing to find numbers of these 
bodies in water cultures, still attached to hyphae which are so com- 
pletely empty that it is only with favorable lighting that their thin 
colorless walls can be seen. So firm is the attachment that vigorous 
shaking is required to release any considerable proportion of the 
spores. It seems probable that in nature the spores are released 
chiefly as a result of the destruction of the hyphae walls by bacteria. 
While there is reason to think that Pythium debaryanum is some- 
times disseminated by wind, it is by no means certain that it is 
through the medium of these spores. It is true that these bodies have 
thinner walls than are commonly found in chlamydospores of some 
other fungi, but they have somewhat thickened walls as compared 
with the vegetative hyphae. and they are commonly intercalary. 
These facts, and the indications that they are better able to with- 
stand unfavorable conditions than are the hyphae, all tend to entitle 
them to rank as chlamydospores. De Bary (5) speaks of them as 
" dauerconidia." Their ability to stand drying is not entirely demon- 
strated, but is indicated by the relative longevity of the fungus on 
different media. On beef agar and on rice, on which no spores are 
