phases of the other and similar parasitic fungi which affect the wheat crop. ------------------------------------------------------------------------ CHAPTER VII. _COMPLEX SMUTS._ SOME of the microscopic fungi are the most unpromising and uninteresting objects to the naked eye which could well be imagined. No one would suppose that the black dust so profusely shed in such genera as _Ustilago_ and _Polycystis_ could be better than as much soot; unless he has learnt by experience not to judge by appearances, but to suspend judgment until examination. The axiom will sooner or later force itself upon all who examine minute objects with the microscope, that all organic nature, whether animal or vegetable, increases in interest in proportion to the magnifying power. Seen by the unaided eye, _moulds_ are all nearly alike, and they seem to be “moulds” and nothing more. “Smuts,” again, sometimes attack one organ, and sometimes another, with very little variation in colour; and “rusts” are all “only rusts” with a paler or more intense rusty tint, until the marvellous combination of lenses, so appropriately named a _microscope_, unfolds a new world, and exposes its new inhabitants unparalleled in the old world of larger life, in form, habit, development, and mystery. A very interesting, though small group of fungi, allied to the preceding, are included botanically under the genus called _Polycystis_, in allusion to the many cells of which the spores are composed.[6] In the most recent work on British Fungi, approximating to a Flora—viz., “Berkeley’s Outlines”—only three species are recorded, whilst the most common, at least around London, is omitted in error; for it could scarcely have been unknown as indigenous to this country. This last is the crow-foot smut (_Polycystis pompholygodes_, Lev.), found on the leaves and petioles of the common creeping buttercup (_Ranunculus repens_), distorting them very much, and also occurring on the wood-anemone and some other Ranunculaceous plants. The leaves and their footstalks, when attacked, become swollen, as if blistered at first, and ultimately burst in an irregular manner, exposing a mass of blackish soot-like dust (Plate IX. fig. 183), which on examination will be found to consist of the many-celled spores alluded to (Plate IX. fig. 184). Each of these spores appears to have a transparent outer membrane, either enclosing an unequal number, from two or three to five or six, distinct cells, compressed together into a spherical form by the outer integument, or the interior is divided by septa into as many cells. Each of these divisions contains a dark brownish endochrome, or cell-contents. As may be anticipated, the spores in all the species associated in this genus are interesting objects for the microscope. The species on the buttercup may be found through the summer and autumn on