To this sub-family belong the majority of the Pyrenomycetes. The
perithecia are of a _firm consistence_ (tough, leathery, woody or
carbonaceous), and of a _dark_ colour. Their _covering_ is _quite
distinct from the stroma_ when this structure is present. The
stromata are sometimes very large, and may be either cushion-like,
crustaceous, upright and club-like, or branched bodies. In general,
small, inconspicuous Fungi, living on dead vegetable matter, sometimes
parasites. Free conidiophores and conidiocarps are known in many
species, and in several, chlamydospore-like forms of reproduction.
Orders 3–18 constitute the Sphæriaceæ of older systematists.
[Illustration: FIG. 120.--_Strickeria obducens_: _a_ a portion
of an Ash-branch with the bark partly thrown off; on the wood
are numerous black perithecia (× 20); _b_ longitudinal section
through a perithecium; _c_ a spore; _d_ longitudinal section
through a pycnidium whose ascospores are being ejected; _e_
portion of the same, with hyphæ and spores.]
Order 1. =Sordariaceæ.=--Fungi living on dung with fragile perithecia,
either aerial or buried in the substratum. The dark brown or black
spores have either a mucilaginous envelope (_Sordaria_, etc.) or
mucilaginous appendages (_Podospora_), by means of which their
expulsion and distribution are promoted.
Order 2. =Chætomiaceæ.= Perithecia fragile, free, bearing on the summit
a tuft of hairs. _Chætomium_, on decaying vegetable matter.
Orders 3–7. _Perithecia scattered or aggregated, situated from the
commencement on the surface of the substratum. Stroma wanting._
Order 3. =Trichosphæriaceæ.= _Trichosphæria parasitica_ (Fig. 121),
on _Abies alba_; _Herpotrichia nigra_ on _Picea excelsa_ and _Pinus
montana_.
[Illustration: FIG. 121.--_Trichosphæria parasitica_: _a_ a
twig of _Abies alba_, with epiphytic mycelium; _b_ a leaf with
mycelium and sporangia (magnified); _c_ a sporangium (× 60); _d_
an ascus with spores (× 550).]
Order 4. =Melanommaceæ.= _Rosellinia quercina_ lives in the roots of
1–3-year-old Oaks, and destroys the plants.