SECT, i CRYPTOGAMS 397 



pycnospores corresponds to that of the spermogonia and spermatia of the Lichens, 

 and they may in part at least be regarded as male organs. 



Claviceps purpurca, the fungus of Ergot, is important on account of its 

 official value. It is parasitic in the young ovaries of different members of the 

 Grarnineae, particularly of Rye. The ovaries are infected in early summer by 

 the ascospores. The mycelium soon begins to form conidia, which are abstricted 

 in small clusters from short lateral conidiophores (Fig. 338 A). At the same 

 time a sweet fluid is extruded. This so-called HONEY-DEW is eagerly sought by- 

 insects, and the conidia embedded in it are thus carried to the ovaries of other 

 plants. The conidial form of this Fungus was formerly regarded as a distinct 

 genus under the name of Sphacelia seyetum. After the completion of this form of 

 fructification, and the absorption of the tissue of the ovary by the mycelium, a 

 sclerotium is eventually formed in the place of the ovary from the hyphae of the 

 mycelium by their intimate union, especially at the periphery, into a compact 

 mass of pseudo-parenchyma (Fig. 107). These elongated dark-violet SCLEKOTIA, 

 which project in the form of slightly curved bodies from the ears of corn, are 

 known as Ergot (Fig. 338, B). The sclerotia, copiously supplied with reserve 

 material (fat), eventually fall to the ground, where they pass the winter, and 

 germinate in the following spring when the Rye is again in flower. They give rise 

 to bundles of hyphse which produce long, stalked, rose-coloured globular heads (C). 

 Over the surface of the latter are distributed numerous sunk perithecia (D, E). 

 Each perithecium contains a number of asci with eight long, filiform ascospores. 

 which are ejected and carried by the wind to the inflorescences of the grass. 



Nectria ditissima C* 4 ) is a very injurious parasitic fungus which inhabits the 

 cortex of various trees and causes the canker of fruit trees. It is propagated 

 in summer by means of slightly curved, fusiform, multicellular conidia, and 

 in winter and spring forms small red perithecia which are closely crowded 

 together. 



OFFICIAL. Ergot is the sclerotium of ('/uric*'/,* jiti,-jni /''. 



Order 4. Tuberaceae (Truffles) ( 6S ) 



The Tuberaceae or Truffle Fungi are saprophytic Ascomycetes whose mycelium 

 occurs in humus soil, particularly in woods. The ascus fructifications familiar 

 under the name of truffles are underground tuberous bodies (Fig.. 339), consisting 

 of a thick, investing layer, enclosing an inner mass in which the club-shaped 

 asci occur (Fig. 339, 2). The asei contain only a small number of spores ; in the 

 case of the true truffles (Tuber) they are usually only four in number, and 

 generally have a spinous or reticulately thickened epispore. When the fructifica- 

 tions are fully mature, the ripe spores lie free within the fructification. 



The fructifications of many of the Tuberaceae are edible C* 3 ), and have an aromatic 

 odour and taste. They are, for the most part, obtained from France and Italy. 

 Of the edible varieties, the most important are the so-called black truffles belong- 

 ing to the genus Tuber, viz. Tuber brumale, mclanosporum, aestivuin, mescn- 

 tericum. The fructifications of these species have a warty cortex of a black, 

 reddish-brown, or dark brown colour. The white truffle, Choiromyces meanJri- 

 formis, the external surface of which is pale brown, is also edible. 



Elaphomyccs granulatus (Boletus cervinus), the yellowish-brown fructifications 

 of which are of the size of a walnut and have a hitter taste, occurs commonly in 

 woods in Europe. It is used in veterinary medicine. 



