BY JOHN MCLUCKIE. 



301 



the hyphae in the cortex with the hyphae in the soil by means of these infecting 

 hyphae through the sheath and the passage-cells. The passage-cells lend them- 

 selves to the easy penetration of the fungTis, in so far as they have thin walls, 

 and dense granular contents, which probably both attract ehemotropically and 

 nourish the hyphae. Lang (1899), in Lyeopodium clavatum, describes a sheath 



Text-fig. 

 Text-fig. 



Text-fig 

 Text-fig 



Text-fig 



8. — Portion jf the hyphae just after penetration into a host 



cell, showing the vacuolated cytoplasm (x 500). 

 9. — Portion of hyphae after a sojourn in a host cell, showing 

 an increased and more dense protoplasmic content with 

 fewer vacuoles (x 500). 



10. — A resting nucleus of the host-cell, with fungal hyphae 

 growing towards it and branching (x 500) . 



11. — A portion of the sheath, endodermis and outer cortex 

 of host showing the fungal hyphae on the surface of the 

 root, in the sheath-cells and penetrating through the 

 passage-cells (s.c.) (x 167). 



12. — Another section showing the fungal hyphae in the passage- 

 cell (s.c.) and penetrating the outer cortical cells (x 500). 



around the hyphae formed from the wall of the cell being penetrated by the 

 fungus, but I have seen no such structure in Dipodium. The hyphae appear to 

 penetrate through portions of the wall which have probably been dissolved by 

 their enzymes. A structure of the nature of an appressorium is formed where 



