FIG. PAGE 1. Agaric in Process of Growth. 17 2. Section of Common Mushroom. 21 3. Sterile cells, Basidia, Cystidium, from _Gomphidius_. 21 4. _Polyporus giganteus_ (reduced). 23 5. _Hydnum repandum._ 24 6. _Calocera viscosa._ 24 7. _Tremella mesenterica._ 24 8. Basidia and spores of _Phallus_. 28 9. Basidia and spores of _Lycoperdon_. 29 10. Threads of _Trichia_. 31 11. _Arcyria incarnata_, with portion of threads and spore. 33 12. _Diachæa elegans._ 34 13. _Cyathus vernicosus._ 34 14. _Cyathus_, Sporangia and spores. 35 15. _Asterosporium Hoffmanni._ 36 16. Barren Cysts and Pseudospores of _Lecythea_. 36 17. _Coleosporium Tussilaginis._ 36 18. _Melampsora salicina_, pseudospores of 36 19. _Cystopus candidus_, conidia of 38 20. _Xenodochus carbonarius_, pseudospore. 38 21. _Phragmidium bulbosum_, pseudospores. 38 22. Pseudospores of _Puccinia_. 40 23. _Thecaphora hyalina_, pseudospores. 41 24. _Æcidium Berberidis_, peridia of 41 25. _Helminthosporium molle_, threads and spores. 42 26. _Acrothecium simplex._ 44 27. _Peronospora Arenariæ._ 44 28. _Polyactis cinerea._ 47 29. _Peziza Fuckeliana_, with ascus and sporidia. 47 30. _Penicillium chartarum._ 50 31. _Mucor mucedo_, with sporangia. 50 32. Small portion of _Botrytis Jonesii_. 54 33. Section of cup of _Ascobolus_. 57 34. Asci, sporidia, and paraphyses of _Ascobolus_. 59 35. Perithecium of _Sphæria_. 61 36. _Uncinula adunca_, conceptacle with appendages. 62 37. _Agaricus nudus._ 66 38. _Scleroderma vulgare_, Fr. 69 39. _Ceuthospora phacidioides._ 69 40. _Rhopalomyces candidus._ 74 41. _Mucor caninus._ 75 42.