MORPHOLOGY OP BLASIA PUSILLA 
431 
scribes a similar strand in Symphyogyna sinnuata and Leitgeb 
describes the cells of this strand in Symphyogyna and states that 
Blyttia (Pallavicinia) and Umbracnlnm (Hymenophyton) have 
similar strands. 
In fresh young plants of Blasia the strands can barely be dis- 
tinguished but in the old dead thalli they stand out on the sur- 
face as white threads. This would indicate that the cell walls 
are more resistant in the strand than in the surrounding tissue 
and the few experiments tried only serve to emphasize this fact. 
Upon the decay of the spongy thallus tissue these strands still 
hold their shape and can easily be picked from the soil surface. 
Drying has the same effect, entirely destroying the soft portion 
but leaving the threads unaffected. 
