358 BOTANY 



particularly of Rye. The ovaries are infected in early summer by the ascospores ; 

 they become overgrown with the hyphal filaments, and in consequence are deformed 

 and reduced to soft, furrowed bodies. The mycelium soon begins to form conidia, 

 which are abstricted in small clusters from short lateral conidiophores (Fig. 280, A). 

 At the same time copious exudations of sweet fluid are extruded. This so-called 

 honey-dew is eagerly sought by insects, and the conidia embedded in itTare 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 segeticm. 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 hyphse of the mycelium by their intimate union, especially in the 

 periphery, into a compact mass of pseudo-parenchyma (Figs. 97, 98, p. 87). In 

 the centre, the tissue of the sclerotium consists of moTe loosely disposed hyphae, 

 and is of a lighter colour. These elongated dark-violet scleroma, which project 

 in the form of slightly curved bodies from the ears of corn, are known as Ergot, 

 Secale comutum (Fig. 280, 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 Eye is again in flower. They give rise 

 to bundles of hyphae which produce long, stalked, rose-coloured globular heads {(J). 

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

 These stalked heads, several of which are formed from the same sclerotia, and 

 elongate until they appear above the ground, are ascogenous fructifications, and are 

 in reality stromata with perithecia. Each perithecium contains a number of asci 

 with eight long, filiform ascospores, which are ejected and carried by the wind to 

 the flowering ears of grain. 



Cordyceps, a genus closely related to Claviceps, is parasitic in the larvae of insects 

 and converts the whole body of the infected larva into a sclerotium, from which is 

 eventually produced a long, club-shaped stroma bearing numerous perithecia. 

 In this case also, a formation of conidia takes place. Botrytis Bassiaiia causes 

 a disease in silkworms known as Muscardine. Of this Fungus only the conidial 

 fructifications are known, which are similarly constructed to those of Claviceps, and 

 grow all over the dead silkworm as a snow-white mould. 



Officinal. — Heade comutum, (Pharm. germ.) or Ergot is the sclerotium of 

 Claviceps purpurea. 



Order 4. Discomycetes 



The Discomycetes are distinguished from the other orders by their open 

 gymn'ocarpous apothecia, which bear the hymenium, 

 consisting of asci and paraphyses, freely exposed on 

 their upper surface. The different groups exhibit great 

 diversity as regards the manner of development of their 

 fructifications. 



The great majoiity of the Discomycetes, of which the 

 genus Pcd-M, with some hundred species, may serve 

 as a type, grow on living or dead vegetable substances, 

 especially upon decaying wood, but sometimes also on 

 Fig. 281. -Pczim anrantiaca. humus soil. They produce saucer-, bowl-, funnel-, or 

 (After Kkombholz, nat. size.) disc-shaped fructifications of a fleshy or leathery con- 

 sistency, and usually of small dimensions. One of the 

 largest forms, Peziza aurantiaca (Fig. 281), has seven centimetre-broad, irregularly 

 bowl-shaped fructifications, which are of a bright orange-red colour, while in most 



