404 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



the spread of an epidemic, and proved successful against Chrysanthemum 

 rust. 



Sulphate of Copper Solution. — Dissolve one pound of sulphate of 

 copper in twenty-five gallons of water, and spray with the solution. 



Powders 



may be applied by dredging from a flour dredger, or pepper pot, or 

 enclosed in a canvas bag. 



David's Powder. — Dissolve four pounds of sulphate of copper in as 

 little water as possible. Slake fifteen pounds of lime in the smallest 

 amount of water necessary, then mix the two preparations thoroughly 

 and let the compound dry, after which it is crushed and sifted and applied 

 in the form of powder. 



Sulphatme. — Mix two and a half pounds of anhydrous sulphate of 

 copper with fifteen pounds of finely powdered sulphur and ten pounds of 

 air-slaked lime. Apply in powder. 



Sulphur. — This is used as a dry powder in the condition known as 

 " flowers of sulphur." It is most effective against the fungi which are 

 epiphytic, in which the mycelium is entirely superficial, forming a dense 

 white felt on the surface of the leaves, as in the Hop mildew, Rose mildew, 

 and Pea mildew. Sometimes finely powdered quicklime may be mixed 

 with the sulphur. 



EXPLANATION OF PLATES I. TO VI. 



{The magnified portions are x 320 diameters, unless loliere otherwise stated.) 



Fig. 1. — Phyllosticta helleborella, Sacc— a, section of perithecium enlarged; b, 

 sporules x 



2. — Septoria Hellebori, Thum. — a, section of perithecium enlarged ; b, 



sporules x 



3. — Coniothyrium Hellebori, C. & M.—a, sporules x 



4. — Ramularia Hellebori, Fckl. — a, threads and conidia x 



5. — Peronospora Ficarue, Tul. Hyphse and conidia x 



6. — Plasmopara pygmcca, Ung. Hypha? and conidia * 



7. — Urocystis Anemones, Pers. — a, glomerules of spores x 



8. — JEcidium punctatum, Pers. Two cluster-cups enlarged. — a, recidiospores x 



9. — Gheosporium Aquilegue, Thum. — a, conidia x 



10. — Ascochyta Aquilegue, Roum. — a, section of perithecium enlarged ; b, 



sporules x 



11. — Phyllosticta Pteonue, S. & S.— a, section of perithecium enlarged; 6, 



sporules x 



12. — Cronartium P<eonia>, Cast. — a, column enlarged ; 6, sporules x ; c, sporules 



germinating x 



18. Clados]>ori>im Paonia-, Pass. Hypha; and conidia x 



14. — Botrytis Pceonice, Oud. Clusters of conidia in situ x 



15. — Peronospora arborcscens, Berk. Portion of thread with conidia x 



16. — Cercosp</ra Jicseda, Fckl. — a, hyphae and conidia x 



17. — Phyllosticta Viola-, Desm. — a, section of perithecium enlarged ; b, 



sporules x 



18. — Septoria Viola, West. — a, section of perithecium enlarged ; b; sporules x 

 \\).— Urocystis Viohe, Fisch. — a, glomerule of spores x 



20. — Puccinia Viohe, Schum. —a, uredospores ; b, teleutospores x 



21. — JEcidium Viola-, Schum. — a, cluster-cups ; b, secidiospores x 



22. — Puccinia (egra, Grove.— a, recidiospores ; b, uredospores ; c, teleutospores x 



