H. W. RICKETT 
small shreds of tissue. In some cases germination occurred, after about 
twice the normal period, and resulted in the production of some abnormal 
plants. I was unable to grow any of these plants to maturity, on account 
of the fungous growth which soon covered and choked them. 
The spores §own in soil germinated usually about a month after sowing, 
in the case of those sown early in the spring. Some sown in early summer 
required three or four months to germinate. The first sign of germination 
is the appearance of a slender germ tube which pushes out through an ir- 
regular ruptured spot in the heavy spore wall. The spores from a green- 
house culture are at this time still united in tetrads, which is contrary to the 
usual description for S. Donnellii under natural conditions (8). The spores 
of a tetrad do not usually all germinate at the same time, and it is rare to 
find a tetrad with all four spores producing young plants. The germ tube is 
filled with dense cytoplasm, and contains from the first an abundance of 
chlorophyll, and there are often present in the early stages globular bodies 
having the appearance of oil droplets. As the tube grows in length, the 
dense contents become gathered at the distal end, leaving the basal end 
almost clear and quite colorless, and the first wall usually cuts off a terminal 
cell which contains all, or nearly all, of the dense cell contents. The 
length to which the germ tube may grow before the first cell division occurs 
varies considerably. This is evident from a comparison of figures i and 2, 
Plate IX. In cases in which I have made measurements, the length of the 
undivided germ tube varies from 0.3 to 1.6 mm. The majority of the germ 
tubes reach a length of about 0.5 mm. by the time of the first cell division. 
In the cases of the abnormal sporelings mentioned above which resulted from 
spores germinated in nutrient solution, the most remarkable feature was 
the great length to which the germ tube attained. It seemed to be able 
to grow indefinitely until the distal end reached the surface of the solution, 
at which time cell division usually occurred (fig. 35, PI. X). Some that 
I have measured reached a length of 7 or 8 cm., and consisted of a single 
long hair-like cell with a small mass of dense green material in the extreme 
distal end, and only to be distinguished by this latter characteristic from 
the rhizoids produced at the same time. 
The first wall is 'transverse, and divides the germ tube into a large clear 
basal cell, from which only the first rhizoid develops and which undergoes 
no further division, and a small, densely-filled terminal cell from which 
the rest of the young thallus develops (fig. 2). The basal cell persists for 
some time, so that the young plant remains attached to the spore wall until 
well along in its development — until about the time when the secondary 
disc begins to be composed of two cell layers. 
The second cell division occurs in a plane parallel to the first, cutting 
the terminal cell into two (fig. 3). About this time the first rhizoid usually 
appears, pushing out from the extreme base of the germ tube, and growing 
rapidly in the opposite direction. It is a simple slender structure, almost 
devoid of granular contents except at the extreme tip. 
