STILBA´CEI.--To this family belongs _Tuberculária vulgaris_ (Pl. VII. fig. 28), which is found upon decaying sticks and branches of trees, especially the lime-tree. It forms little firm red knobs or tubercles, each of which is a receptacle. On making a section of a receptacle (Pl. VII. fig. 29), the interior is seen to be paler than the bright red surface, and a short broad stalk comes into view. The receptacle is composed of crowded cell-filaments, so short near the base as rather to resemble cellular tissue (fig. 30); but towards the surface the filaments become extremely slender and branched; and each branch is terminated by a minute oblong spore, or a short row of them (fig. 31). If a stick with this Fungus upon it be kept for some time in a damp place, short whitish fibres, branched at the ends, and visible to the naked eye, will be seen sprouting from around the base of the receptacle (Pl. VIII. fig. 1). These, when examined under the microscope, appear composed of fine filaments (Pl. VIII. fig. 2), resembling those of _Tubercularia_, and having the minute spores at the ends. After a considerable time, the entire receptacle of the _Tubercularia_ becomes resolved into these fibres. In this state the Fungus assumes the characters of an _Isária_, a genus of a different family of Fungi (_Isariacei_), so that we have here an _Isaria_-form of _Tubercularia_. Sometimes the tubercles of the _Tubercularia_ become darker, almost black, harder, and granular on the surface. On making a section of them in this state, the whole of the under portion of the surface is found to contain little roundish capsules, containing asci and spores, and it constitutes _Sphæ´ria fragifor´mis_ (Pl. VII. fig. 32). As the _Sphæria_ is the more complex and highly organized condition of this Fungus, the other two conditions must be regarded as forms, and not as species of separate genera. DEMATIE´I.--In this family the filaments upon which the spores are placed are not compacted as in _Tubercularia_, but separate; and they are of a dark brown or black colour. _Sporoc´ybe alternáta_ (Pl. VII. fig. 18) is occasionally found upon decaying vegetable substances, forming little black velvety spots or patches. The mycelial filaments are exceedingly minute, septate, tapering at the ends, and terminated by a little tuft of pear-shaped cells, from which the black simple spores arise singly. PLATE VIII. [PAGE 104.] FUNGI. Fig. 1. _Isaria_-form of _Tubercularia_. 2. _Isaria_-form of _Tubercularia_, filaments. 3. _Aspergillus glaucus._ 4. _Aspergillus glaucus_, filaments and heads of spores; _a_, separate spores. 5. _Aspergillus glaucus_, head of spores. 6. _Peziza omphalodes._ 7. _Peziza stercorea._ 8. _Peziza stercorea_, cup (receptacle). 9. _Peziza stercorea_, asci and paraphyses. 10. _Peziza stercorea_, divided receptacle. 11. _Peziza stercorea_, bristles. 12. _Dothidea typhina_, on leaf-stalk ofgrass. 13. _Dothidea typhina_, surface of patch (stroma).