_Sphærotheca pannosa_ occurs on the leaves of Roses, and on the fruit of Peaches and Apricots. _S. castagnei_ on _Humulus_, _Cucumis_, etc.--_Erysiphe tuckeri_ grows on the leaves and fruit of the Vine; it spins its hyphæ over the bunches of grapes, curtails their growth, and causes them to burst, and to become decayed and rotten (Grape-disease). The Fungus was first noticed in England in 1845, and later was found in all countries where grapes are grown. It is only known in the conidial form (“Oidium tuckeri”). Many other species of _Erysiphe_ are found on herbaceous plants.--_Microsphæra_ has appendages which are repeatedly forked at their extremities. _M. grossulariæ_ on _Ribes grossularia_.--_Uncinula_ has appendages with spirally-coiled extremities; on _Salix_ and _Acer_.--_Phyllactinia_ has a circle of bristle-like appendages with dilated bases. _P. guttata_ on _Corylus_, _Fraxinus_, _Fagus_, etc. Order 2. =Perisporiaceæ=, Moulds and Mildews. A group of Fungi widely distributed and found in all situations. Usually they have a well-developed surface mycelium, and small, round, seldom conspicuous ascocarps, containing ovoid, pulley-like spores. They are partly saprophytic, partly parasitic, in the latter condition having a brown mycelium. [Illustration: FIG. 110.--_Eurotium glaucum_: _a_ longitudinal section of a half-ripe ascocarp, bounded externally by a well-defined layer of cells, enclosing asci in various stages of development; _b_ a semi-ripe, _c_ an almost ripe ascus; _d_ and _e_ spores seen from the edge and side; _f_ germinating spore twenty-two hours after been sown in plum juice.] _Eurotium glaucum_ (= _E. herbariorum_, Figs. 109, 110) and _E. repens_ live on dead organic matter, preserved fruits, etc. The conidial forms of both species are known as “Moulds” (Fig. 109), and formerly were described under the name “_Aspergillus glaucus_.” The conidia for some time remain attached to each other in chains (Fig. 109 _a_); they are abstricted from sterigmata arranged radially on the spherical, swollen end of the conidiophore. The small yellow or brownish ascocarps are frequently found in herbaria, especially when the specimens have been insufficiently dried. _Aspergillus fumigatus_ and others are pathogenic, causing mycosis in warm-blooded animals. [Illustration: FIG. 111.--_Penicillium crustaceum_: _a_ conidia (× 300); _b_ germination of conidia; _c_ small portion of mycelium, produced from a conidium at *, with five conidiophores; _d_ young conidiophore (× 630), a flask-shaped cell is abstricting a conidium; _e_ the same conidiophore after 9–10 hours.]