LYMAN: STUDIES OF HYMENOMYCETES. 
165 
Formation of bulbils .— A sparse mycelium develops over the sur¬ 
face of the culture medium, and after about ten days it takes on a 
powdery appearance under a hand lens. Microscopic examination 
shows that the hyphae of the secondary mycelium are putting forth 
numerous, short, knotted outgrowths (pi. 19, fig. 35-37), which branch 
profusely and bulge irregularly to form close bundles of a highly 
distorted appearance. The knotted closely compacted elements of 
each bundle become cut up into cells which adhere to one another, 
and all trace of the original branch is soon lost (pi. 19, fig. 35-40). 
The cells enlarge and thicken their walls, and the bundle becomes a 
globose or irregularly shaped cluster of brown thick-walled cells. The 
production is so profuse that many bulbils may appear on one hypha, 
either forming on short lateral branches, or engulfing the hypha itself, 
which in this case does not run through the bulbil as an axis but com¬ 
pletely loses its individuality in the elements of the developing cluster. 
Practically the whole visible mycelium may thus become swallowed 
up. Occasionally neighboring clusters become fused, due to pressure 
at time of formation, but usually adjacent bulbils remain independent 
and preserve their unity of origin from a single branch. 
Mingled with the perfect bulbils of globose form, are many of 
abnormal appearance as to shape, size, arrangement of cells, etc., 
some being reduced to a straight or curved row of several cells, which 
have the size and appearance of bulbil cells, but are not compacted 
into a cluster (pi. 19, fig. 42). Such numerous variations in the char¬ 
acter of the bulbils are to be expected from their method of formation. 
There is no characteristic primordium in this species like the coiled 
hypha of Helicosporangium (see p. 196), which would naturally yield 
a more uniform product. The initial hypha may sometimes chance to 
bend on itself in a helicoid fashion (pi. 19, fig. 35), but there is no 
general regularity in its appearance or behavior. The bulbil arises 
simply as the result of a close irregular branching and knotting of the 
parent hypha. 
Cultivation of bulbils .— The exact length of time during which 
bulbils will retain the power of germination was not determined, but 
it is considerable. Those taken from a dried-up agar tube nearly 
three years old still germinate vigorously. The process of germi¬ 
nation is very rapid in all media; ten to twelve hours are sufficient 
for the formation of germ tubes as long as the diameter of the bulbil 
(pi. 19, fig. 43). Germ tubes not only arise from the external cells. 
