xii Minnesota Plant Life. 



FIG. 9. Portion of a pond-scum thread, showing how it is made up of 

 transparent-walled cells with a coiled green ribbon in each, 

 much magnified. After Atkinson 34 



FIG. 10. Patches of pond-scum floating in a tank. A lime-encrusting 

 alga grows on the boards up to high-water mark. Near 

 Minneapolis. After photograph by Mr. R. W. Squires 35 



FIG. ii. Patches of wheat-rust, natural size and enlarged. The red rust 



stage. After Atkinson 51 



FIG. 12. Patches of wheat-rust, natural size and enlarged. The black 



rust stage. After Atkinson 51 



FIG. 13. Wheat-rust in its barberry-leaf stage; to the left a barberry 

 leaf with diseased spots; in the middle, a single spot with 

 cups; to the right, two of the cups, in top view slightly mag- 

 nified. After Atkinson 52 



FIG. 14. Magnified section through a cluster-cup of the wheat-rust in its 

 barberry-leaf stage. Shows chains of spore-cells. The large 

 cells at the sides are those of the barberry leaf much magni- 

 fied. After Atkinson 53 



FIG. 15. Growth of club-fungi on decaying wood. After Lloyd 56 



FIG. 16. Shelf-fungus growing on dead stump of oak tree. After pho- 

 tograph by Hibbard 57 



FIG. 17. Upper and under sides of mushroom-like pore-fungus. After 



Lloyd 59 



FIG. 18. A pore-fungus lying flat upon a decaying branch. After Lloyd 60 

 FIG. 19. Deadly variety of mushroom. After Atkinson. Bulletin 138, 



Cornell Ag. Exp. Station. This is sometimes known as the 



"poison cup" 61 



FIG. 20. Under side of two mushroom-fruits. After Atkinson. Bulletin 



138, Cornell Ag. Exp. Station 62 



FIG. 21. Common edible mushroom. After Atkinson. Bulletin 138, 



Cornell Ag. Exp. Station 6 3 



