8 Scientific Proceedings, Royal Dublin Society. 
surrounded by the starch grains, some of which also lie scattered 
through the protoplasm. Numerous fungal hyphe are observed 
passing more or less directly through these outer layers.. This 
is an important fact, and is especially obvious in transverse 
sections of the rhizome in the neighbourhood of a papilla. 
2. Internal to the cells constituting these outer tissues there 
occur one or more layers of cells, usually three, which have thin 
cellulose walls, and contents markedly different from those of the 
outer layers ; each cell is filled with a coiled mycelium ; the cell sap 
is scanty, and the hyphz may be observed piercing the cell walls. 
Fic. 8. 
Surface of a nearly median section through lobes of the rhizome, showing the dis- 
tribution of the mycorhiza in the tissues, as indicated by the light bands, (x 25.) 
Where the hyphe pass straight through from one cell to 
another, there is a paucity or a marked absence of starch grains 
(fig. 4). 
3. More internally we come to cells which have a very different 
appearance ; these cells are large, thin-walled, and provided with 
abundant protoplasm; starch grains are numerous. ‘The latter 
seem to increase in the cells in proportion as the hyphe disappear 
(fig. 5, a). The hyphe in no instance were observed to swell into 
bladder-like bodies in the neighbourhood of the nuclei, the filaments 
being practically of the same width in all parts of the coil. The 
mycelium may be observed in all stages of degeneration in the 
