[Illustration: FIG. 105.--Section of _Tubercularia_. _c._ Threads with conidia.[K]] Passing to the other bodies, which are of a deeper colour, it will soon be discovered that, instead of being simple rounded heads, each tubercle is composed of numerous smaller, nearly globose bodies, closely packed together, often compressed, all united to a base closely resembling the base of the other tubercles. If for a moment we look at one of the tubercles near the spot where the crimson tubercles seem to merge into the pink, we shall not only find them particoloured, but that the red points are the identical globose little heads just observed in clusters. This will lead to the suspicion, which can afterwards be verified, that the red heads are really produced on the stem or stroma of the pink tubercles. A section of one of the red tubercles will show us how much the internal structure differs. The little subglobose bodies which spring from a common stroma or stem are hollow shells or capsules, externally granular, internally filled with a gelatinous nucleus. They are, indeed, the perithecia of a sphæriaceous fungus of the genus _Nectria_, and the gelatinous nucleus contains the fructification. Still further examination will show that this fructification consists of cylindrical asci, each enclosing eight elliptical sporidia, closely packed together, and mixed with slender threads called paraphyses. Here, then, we have undoubted evidence of _Nectria cinnabarina_, with its fruit, produced in asci growing from the stroma or stem, and in intimate relationship with what was formerly named _Tubercularia vulgaris_. A fungus with two forms of fruit, one proper to the pink, or _Tubercularia_ form, with naked slender conidia, the other proper to the mature fungus, enclosed in asci, and generated within the walls of a perithecium. Instances of this kind are now known to be far from uncommon, although they cannot always, or often, be so clearly and distinctly traced as in the illustration which we have selected. [Illustration: FIG. 106.--D. _Nectria_ surrounding _Tubercularia_; E. tuft of _Nectria cinnabarina_; F. section of stroma; G. ascus and paraphyses.] It is not uncommon for the conidia of the _Sphæria_ to partake of the characteristics of a mould, and then the perithecia are developed amongst the conidial threads. A recently recorded instance of this relates to _Sphæria Epochnii_, B. and Br.,[L] the conidia form of which was long known before the _Sphæria_ related to it was discovered, under the name of _Epochnium fungorum_. The _Epochnium_ forms a thin stratum, which overruns various species of _Corticium_. The conidia are at first uniseptate. The perithecia of the _Sphæria_ are at first pale bottle-green, crowded in the centre of the _Epochnium_, then black green granulated, sometimes depressed at the summit, with a minute pore. The sporidia are strongly constricted in the centre, at first uniseptate, with two nuclei in each division.