52 MINNESOTA BOTANICAL STUDIES. 



after leaving the end of the elater. One of these strands di- 

 vides again (b) and the other at a point still farther on (c). One 

 of the branches from b and one from c meet the second one from 

 b at d, while the second one from c returns the length of the 

 elater and fuses with the original fibre at a. 



Sometimes the spiral band splits into three or four divisions 

 {PL V. figs. 2, a; 6, a; PL IV. fig. 15, a). This generally occurs 

 with the throwing out of a branch (PL IV. fig. 8, a; fig. 14, a). 

 The general rule appears to be that the two spiral threads 

 start from the end of the elater, divide once or twice near the 

 middle, part going directly into each branch of the elater, but 

 sometimes a strand will traverse, in turn, two parallel branches 

 without extending into the body of the elater at all {PL IV. fig. 

 4, «; fig. 15, b; PL V. fig. 7, a). 



It seems generally to happen that the most interesting speci- 

 mens are found near the edge of the coverglass where evapora- 

 tion takes place very rapidly. "When the water is renewed such 

 a disturbance is caused that it is almost impossible to keep the 

 object in view until it comes to rest again, and even then it is 

 likely to be in an entirely different position so that the first 

 drawing cannot be finished; so it is necessary to be very expe- 

 ditious in the work. However, in one or two cases, I succeeded 

 in getting two drawings of the same elater from different 

 views {PL V. figs. 4 and 5). This brings out the manner of 

 branching in the spirals much more clearly. Two bands are 

 observed to coalesce (a) and immediately separate again, one 

 of the latter branches dividing a second time (&) to form a loop 

 around the end of the tube. The other branch joins with a 

 third (c) band which has traversed the length of the elater, 

 forming likewise a loop which appears from one view (fig. 4) 

 to lie upon a fiat surface of the wall, while in the other position 

 (fig. 5) a bulging out is apparent, evidently the beginning of a 

 new branch. 



In a single case {PL IV. fig. 6) the spiral systems of two well 

 developed branches of an elater were entirely independent of 

 each other. This, perhaps, might seem to have the appearance 

 of being due to fusion between two elaters, but if we follow the 

 above mentioned view that the wall and not the fibre takes the 

 initiative in growth, it becomes a simple case of branching. 



In PL IV., figs. 4, 8 and 9 and in PL V, fig. 13 were all 

 taken from the same sporogonium. PL IV. figs. 3 and 11 were 

 from the same head. The first five elaters represented in PL 

 ]'. were taken from the same sporogonium. About one-fourth 



