In _Elaphomyces_ (Stag-Truffle) the fruit-body has a corky external layer, and is inedible. Some of the species are found in this country. _E. granulatus_ is parasitic on the roots of the Fir. Family 3. =Pyrenomycetes.= In this family the hymenium is enclosed in small fruit-bodies, _perithecia_ (Fig. 120 _b_), which appear to the naked eye as small dots. In shape they resemble a globe or a flask with a narrow mouth, through which the spores are ejected (peronocarpic ascocarps). Different kinds of reproduction--conidia, pycnidia (chiefly with microconidia), chlamydospores, and perithecia--are found in the same species. The various stages in the life-history of these Fungi are so dissimilar, that formally they were considered to be different genera. Ergot furnishes a very good example. [Illustration: FIG. 114.--A small portion of an ovary attacked with _Claviceps purpurea_ (_Sphacelia_).] [Illustration: FIG. 115.--An ovary with the conidial stage of _Claviceps purpurea_ (_Sphacelia_).] This family may be subdivided into 3 sub-families. Sub-Family 1. =Hypocreales.= The perithecia are _pale, fleshy, brightly coloured_, and generally aggregated on a stroma. Conidia and chlamydospores occur very frequently. Only one order. Order. =Hypocreaceæ.= In this order the majority are parasites upon Flowering-plants (_Nectria_, _Polystigma_, _Epichloë_, _Claviceps_); but some are parasites upon Fungi (_Hypomyces_, _Melanospora_), or upon insects (_Cordyceps_). [Illustration: FIG. 116.--_Claviceps purpurea. A_ Sclerotium with stromata (_cl_) (× by 2). _B_ Stroma divided longitudinally to show the perithecia (_cp_). _C_ A perithecium with the surrounding hyphæ (_hy_). _D_ An ascus ruptured, with the eight filamentous ascospores emerging.]