=Uromyces Polygoni=, Fuckel. KNOTGRASS RUST; cauline; sori elongated and confluent, convex, surrounded by the remains of the ruptured epidermis; sporidia subglobose or globose, smooth, yellowish-brown; pedicels very long, thickened, hyaline, persistent. _Capitularia Polygoni_, Rabh.—On the stems of _Polygonum aviculare_. October. Common. * * * * * =Cystopus spinulosus=, De Bary. THISTLE (WHITE) RUST; conidia in time much elongated; sori erumpent on both surfaces of the leaves, white; oospores globose; epispore brown; tubercles minute, solid, very prominent, often acute and spinulose.—On Thistles. Bungay, Suffolk. September, 1865. * * * * * =Peronospora candida=, Fuckel. PRIMROSE MOULD; densely cæspitose, white; threads erect, dichotomously branched; ultimate branchlets short, spreading; sporidia ovate.—On leaves of Primrose. Near Corwen, N. Wales. July, 1866. The following genus is entirely new to Britain. Its position is next to _Microsphæria_ at page 219. PODOSPHÆRA, _Kunze_. Mycelium effuse, web-like, evanescent; conceptacles sphærical, containing one subglobose 8-spored sporangium; spores ovate; appendages few, dichotomous, thickened at their extremities, hyaline. =Podosphæra Kunzei=, Lév. PLUM BLIGHT; amphigenous; conceptacles minute, scattered, globose; appendages three times the length of the diameter of the conceptacles.—On leaves of _Prunus domestica_. Shere, Surrey. Sept., 1865. (_Dr. Capron._) =Podosphæra clandestina=, Lév. HAWTHORN BLIGHT; amphigenous; conceptacles minute, globose, scattered; appendages (8-10) equal in length to the diameter of the conceptacles; branches short and rounded at their extremities.—On leaves of the Hawthorn. Upper Holloway. October, 1864; Shere, Surrey, September, 1865. (_E. C._) * * * * * =Uncinula Wallrothii=, Lév. SLOE BLIGHT; amphigenous; mycelium web-like, evanescent; conceptacles minute, scattered; sporanges 12-16, pear-shaped, 6-spored; appendages numerous, twice the length of the diameter of the conceptacles.—On leaves of the Sloe, _Prunus spinosa_. Shere, Surrey. October, 1865. (_Dr. Capron._) * * * * * =Microsphæria comata=, Lév. SPINDLE BLIGHT; hypophyllous; mycelium web-like, fugacious; conceptacles scattered, minute, globose; sporanges 8, ovate, with a beak-like termination at their base, 4-spored; appendages few, six times the length of the diameter of the conceptacles.—On _Euonymus Europæus_. Shere, Surrey. August, 1865. (_Dr. Capron._) * * * * *