Well may the reader remark on arriving thus far, “Does all this examination and detail refer to the fruit borne in the little blackish spots on bramble leaves, which I have hitherto overlooked?” Ay, and to several similar spots on other plants. Examine carefully the raspberry leaves in your garden, and you will probably find similar, but smaller, pustules also on the under surface (Plate III. fig. 42). We say _probably_, because none of our British species seem to be equally uncommon with this. During the past year we examined hundreds of plants, and did not find a single pustule. This species was named by Dr. Greville _Aregma gracilis_, which name it still continues to bear (fig. 43). Such a fate will not await you if you should proceed in the autumn to some chalky district where the burnet is common. Go, for instance, to Greenhithe or Northfleet, on the North Kent Railway, in August or September, where the burnet is plentiful, and the leaves will present the appearance of having been peppered beneath, from the number of minute pustules of the burnet brand scattered over the under surface (fig. 30, upper leaflets). Or if you prefer collecting nearer home, visit some neighbouring garden, if your own does not contain many roses, and the leaves will be found equally prolific in an allied species (fig. 36). Should gardens and roses be alike unattainable, any bank or wood will furnish the barren strawberry (_Potentilla fragariastrum_), and during the latter part of the summer, or in autumn, another species of _Aregma_ will not be uncommon on the under surface of the leaves (fig. 33). All these species will be found accompanied by the orange spores of species of _Lecythea_, which some mycologists consider to be distinct fungi, and others to be merely forms or conditions of _Aregma_. These spores are represented in Plate III. figs. 31, 34, 37, and 40. From the magnified figures of the spores of the different species of _Aregma_ (figs. 32, 35, 38, 41, and 43), it will be apparent that they have all certain features in common, _i.e._, cylindrical spores containing from three to seven cells. This may be called the _generic_ character, common to all the species of the genus _Aregma_. Again, each species will be observed to possess its own distinct features, which may be termed its _specific_ character. In one, the apex of the spores will be obtuse, in another acutely pointed, in another bluntly pointed, &c. In one species the number of cells will usually be four, in another five or six, in another seven or eight. The stem in one species will be slender and equal, in another thickened or bulbous. So that in all there will be some permanent peculiarity for each not shared by the others.