164 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
formation; and (4) by the formation of the spores separately and later¬ 
ally on the sporophore in most cases, together with a tendency for 
adjacent spores to assume a definite position with regard to one another. 
Hence the writer is of the opinion that we here have to do with repro¬ 
ductive bodies which have advanced beyond the grade of oidia, and, 
while not coming strictly within our definition of conidia, merit the 
latter title rather than the former. The significance of this inter¬ 
pretation will be seen in the discussion to follow concerning the nature 
of oidia and chlamydospores (see p. 194). 
Bulbils .— In nutrient-agar tubes and in cultures upon wood, the 
secondary mycelium after a few days’ growth produces small bulbous 
sclerotia or bulbils. These are formed in such quantities in well 
nourished cultures as to cover the substratum, completely effacing 
the mycelium from view, and forming a layer from 1 to 3 mm. in thick¬ 
ness. Bulbils never appear on the primary mycelium but invariably 
occur upon the secondary, without reference to whether the culture 
originates from a basidiospore, a conidium, a bulbil, or a transfer of 
vegetative mycelium. ,They appear on all media, even a very attenu¬ 
ated decoction producing a moderate quantity. Hence we may say 
that bulbils are normal and unfailing productions under all culture 
conditions, and the same appears to be true under natural conditions 
also, for careful examination of the basidiosporic fructifications col¬ 
lected in the field by the writer revealed bulbils accompanying the 
hymenium and partially overrun by it. 
The bulbils (pi. 19, fig. 40) are reddish brown or chocolate-colored 
clusters of cells, more or less globose in shape, and usually 65-80 ji in 
diameter, although ranging as high as 220 fi. The cells composing 
the cluster vary in diameter from 10-25 //, and have thick brownish 
walls, and very dense granular contents; although angular through 
mutual pressure they are not closely enough compacted to obliterate 
entirely the intercellular spaces (pi. 19, fig. 41). The bulbils are 
frequently very irregular in shape due to the unsymmetrical arrange¬ 
ment of the cells, and to the bulging of the free outer walls. There is 
no distinction between internal and external cells of the cluster. The 
external cells first lose their contents through age, and hence old bul¬ 
bils frequently present the false appearance of having an irregular 
cortex of empty cells; but at the time of maturity the cells of the 
cluster are quite undifferentiated as regards size, shape, contents, or 
power of germination. 
