442 



BOTANY 



PART IT 



an antheridium and a carpogonium provided with a trichogyne. The walls of the 

 asci and the surrounding pseudo-parenchyma disappear in the ripe fructification 

 which opens irregularly by the rupture of the peripheral layer. 



2. The Elaphomycetaceae have subterranean, truffle-like fructifications, the 

 peridium of which is sharply marked off from the powdery mass of spores derived 

 from the ascogenous hyphae. Elaphomyces granulatus (Boletus cervinus}, the 

 yellowish-brown fructifications of which are of the size of a walnut and have a 

 bitter taste, occurs commonly in woods in Europe. It is used in veterinary 

 medicine. 



FIG. 384. Conidiophores of Aspergillus herbariorum (to the^left) and Penicittium crustaceum 



(to the right). 



3. The Terfeziaceae are distinguished from the preceding group by the peridium 

 of the fructification not forming a sharply distinct layer. Species of Terfezia with 

 edible truffle-like fructifications occur in the Mediterranean region. 



Order 3. Pyrenomycetes 



The Pyrenomycetes comprise an exceedingly varied group of Fungi, some 

 of which are parasitic upon different portions of plants, and others are saprophytic 

 upon decaying wood, dung, etc., while a few genera occur as parasites upon the 

 larvae of insects. The flask-shaped fructifications or perithecia are characteristic 

 of this order. The perithecia are open at the top, and are covered inside, at the 

 base, with a hymenial layer of asci and hair-like paraphyses (Fig. 385). The 

 lateral walls are coated with similar hyphal hairs, the periphyses. The ascospores 

 escape from the perithecia through the aperture. 



The simplest Pyrenomycetes possess free perithecia (Fig. 385) which are usually 

 small and of a dark colour, and grow singly on the inconspicuous mycelium (e.g. 

 Nectria, Sphaeria, and Podospora}. In other cases the perithecia are in groups 

 embedded in a cushion- or club-shaped, sometimes branching, mass of compact 

 mycelial hyphae having a pseudo-parenchymatous structure. Such a fructification 

 is known as a STIIOMA. 



In the life-history of most Pyrenomycetes the formation of perithecia is pre- 



