1923] Fruit-body of New Parasitic Rhizopogon 109 



(Below) A more highly magnified view of a part of the section shown in lower 

 figure of plate 3. The infecting fungus can be seen invading the cortical 

 area in single threads, x 190. 



Plate 5 



(Above) Section through a plant older than the one in plate 4. The hyphae are 

 now invading in almost solid sheets along the cell walls, x 240. 



(Below) Longitudinal section of a fully grown fruit-body, showing hymenial 

 chambers, the pine tissue completely destroyed, x 5-5. 



Plate 6 

 (Above) Showing tramal plates, hymenium, and chambers, x 250. 

 (Below). Part of above. Sterigmata can be seen near the middle of the figure. 

 • X 500. 



Plate 7 



Fig. 1. Fungal threads attacking cortical cells of the pine, in same stage as 

 shown in upper figure on plate 5. The fungal threads force their way be- 

 tween and over the pine cells which are the unshaded areas in the figure. 

 x690. 



Figs. 2 «& 3. Basidia with nearly mature spores. 



Fig. 4. Young basidia. x 1290. 



Fig. 5. Mature spores, x 1290. 



Fig. 6. Tramal thread, showing nuclei, x 1290. 



Fig. 7. Trama and hymenium of mature plant, some of the basidia with two, 



others with four sterigmata. x 1290. 



Figs. 4-6 stained to show nuclei. 



