An allied species constitutes the hop-mildew, a visitation with which some of our Kentish friends are too familiar. This is not a prejudiced species in the choice of its habitation, since it is found on many other plants, where it flourishes with equal vigour. The meadow-sweet, burnet, scabious, teasle, dandelion, and other composite plants, plantain, and plants of the cucumber family, all suffer more or less from its roving disposition. The mycelium of whitish threads is even more conspicuous than in the last species, but the conceptacles are often not to be found at all. These are also very minute and most common on the under surface of the leaves. The appendages, or fulcra, are simple, floccose (fig. 217), and coloured. The sporangia are found singly in each conceptacle, and each, sporangium contains eight spores. An autumnal stroll amongst hazel-bushes, when the nuts are ripe, will lead, if the nuts are not a greater attraction, to the discovery of whitish, patches on the under surface of the leaves, caused by the mycelium of the hazel mildew (_Phyllactinia guttata_, Lev.). These patches are less distinct and conspicuous than in many other species, but the little blackish dots of the conceptacles may be distinguished by sharp eyes without the use of the lens. Though possessing a decided preference for the hazel, this species is also found on the green leaves of the hawthorn, ash, elm, birch, sallow, beech, oak, and hornbeam. The conceptacles are larger than in the two preceding species, and somewhat depressed above. The appendages are few (fig. 219), radiating, rigid, and acicular, or like needles. Each conceptacle contains eight or more sporangia, and each sporangium has from two to four spores (fig. 220). This species being very common, its conceptacles large, and produced copiously, and its appendages distinct, it will prove a good type with which the student of these fungi may commence his examinations. This is the only representative which we possess of the genus established by M. Leveille for such of the _Erysiphei_ as have the conceptacle depressed, and the appendages rigid and simple; by which features it is distinguished from genuine species of _Erysiphe_.