ON THE GERMINATION OF THE UREDINES. 
139 
active tube continued making spiral turns upon itself like a cork- 
screw. The actual number of turns varied, as did their direction, 
whether from right to left or left to right. Very often, too, the 
tube would turn two or three times in one direction, and then, 
reversing its movement, take a few turns in the opposite direction. 
The diameter of the helix, too, was subject to considerable varia- 
tion. The sides of the tube were parallel to each other, and its 
diameter uniform. At the extreme end, which was blunt, there 
now appeared numerous irregularities, which were incipient 
branches (fig. 5). Not infrequently the end of the tube trifurcated 
in the manner of a trident (figs. 6 and 7). Usually one only of 
the main branches of the trident continued its growth, the others 
remaining rudimentary. From this point all semblance of regu- 
larity in the contour of the tube was lost, and it gave off lateral 
branches somewhat after the manner of a stag’s horn. The extremity 
of the tube did not even now lose its tendency to convolute, 
although this movement is considerably diminished (fig. 8). The 
yellow endochrome had by this time all accumulated in the ir- 
regular branched part of the tube, for although the lower 
portion above the septum was obviously not empty, yet the only 
distinctly yellow colouration was to be seen in the distal branched 
portion. 
It is obvious that the spiral movements above described are of 
great importance to the fungus, as by them the growing mycelial 
tube has the chance of its catching on any irregularity of the cuticle 
of the best plant greatly increased. This catching power is enhanced 
too by the trident-like terminal extremity with its irregular branched 
outline. It is possible that the non-development of some of the 
terminal branches is not a purely accidental circumstance, but a 
provision by which the mycelium may become fixed upon the leaf, 
while the favoured branch is penetrating it. The ultimate changes 
which were observed in the mycelial tube were simply that it 
appeared to become septate. 
Similar results to the above were obtained from watching the 
germination of the Uredo of Coleosporium tussilaginis, Lev. ; 
of Fhragmidium mucronatum , Link. ; of Uromyces appendi culata. 
Lev. ; and of dZcidium crassum , Pers. 
On the 12th and 13th August, 1881, some spores of Uredo 
linearis were observed to germinate in quite a different manner, 
for instead of producing the irregularly outlined branches (the 
stag’s horn branches), the terminal extremity of the tube became 
expanded in a globular manner, into which all the yellow endo- 
chrome accumulated (plate 159, figs. 10-12). Often a secondary 
globular expansion took place at a lower part of the tube (figs. 11 
and 12). Whether these bodies were really secondary spores, 
and, as such, fell away from the tube, or whether they were simply 
reservoirs into which the endochrome was accumulated previous to 
making a fresh departure in mycelial development, could not be 
clearly made out, but as they were not observed presenting any 
