DIV. I 



THALLOPHYTA 



443 



ceded by the' production of various accessory fructifications, particularly of conidia, 

 which are abstricted in different ways, either directly from the hypliae or from 

 special conidiophores, and assist in disseminating the fungus. The conidiophores 

 are frequently united in distinct, conidial fructifications. A special form of such 

 fructifications are the PYCNIDIA produced by many genera. They are mall 

 spherical or flask-shaped bodies which give rise to branched hyphal filaments from 

 the apices of which conidia, in* this case termed PYCNOSPORES or PYCNOCONIDIA, 

 are abstricted (Fig. 386). The structure of the pycnidia and pycnospores corre- 

 sponds to that of the spermogonia and spermatia of the Lichens, and they may 



be regarded as the original male organs. 



Claviceps purpurea, the fungus of Ergot, 

 is important on account of its official 

 value. It is parasitic in the young ovaries 

 of different members of the Gramineae, 

 particularly of Rye. The ovaries are in- 

 fected in early summer by the ascospores. 

 The mycelium soon begins to form conidia, 

 which are abstricted in small clusters from 

 short lateral conidiophores (Fig. 387 A}. 



FIG. 385. Peritbecium ofPodosporafimiseda 

 in longitudinal section, s, Asci ; a, 

 paraphyses ; e, periphyses ; m, mycelial 

 hypliae. (x 90. After v. TAVEL.) 



FIG. 386. 1, Conidiophore abstricting conidia, 

 from a pycnidium of Cryptospora hypodermia. 

 (x 300. After BREFELD.) 3, Pycnidium of 

 Stricter-id obducens in vertical section, (x 70. 

 After TULASNE.) 



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. 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 hypliae of the mycelium by their intimate union, 

 especially at the periphery, into a compact mass of pseudo-parenchyma (Fig. 36). 

 These elongated dark-violet SCLEROTIA, which project in the form of slightly 

 curved bodies from the ears of corn, are known as Ergot, SECALE CORNUTUM 

 (Fig. 387 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 hyphae which produce long-stalked, rose-coloured globular heads (C}. Over 

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



