compacted together to form the
stem and head. Some of these threads are simple, others are branched,
bearing here and there upon them delicate little bodies, which are
readily detached, and which form the mealy bloom which covers the
surface. These are the conidia, little slender cylindrical bodies,
rounded at the ends.

[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 sphaeriaceous 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.