. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. in] PLECTASCALES 73 enclosed them between glass plates so as to reduce the entrance of air, and the development of conidia. Similarly Zukal a few years later obtained sclerotia by excluding air. The formation of the perithecia in Brefeld's material was initiated by the appearance of pairs of simple, stout hyphae which twisted round one another (fig. 32), and from one or both of which branches later arose. Brefeld regarded them as possibly oogonial and antheridial. A further study of these organs, the simple form of which suggests a compar
. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. in] PLECTASCALES 73 enclosed them between glass plates so as to reduce the entrance of air, and the development of conidia. Similarly Zukal a few years later obtained sclerotia by excluding air. The formation of the perithecia in Brefeld's material was initiated by the appearance of pairs of simple, stout hyphae which twisted round one another (fig. 32), and from one or both of which branches later arose. Brefeld regarded them as possibly oogonial and antheridial. A further study of these organs, the simple form of which suggests a comparison with Gymnoascus, is much to be desired. Penicillium glaucum includes several biological species or strains, and it is quite possible that Brefeld's success depended not only on the methods employed, but also on the use of a fortunate variety. Klocker, in 1903, obtained asci in his new species P. Wortmanni, and another new and very curious ascigerous species, Penicillium vermiculatum, was described by Dangeard in 1907. The vegetative cells, unlike those of related forms, are uninucleate and bear a very scanty supply of conidia. Perithecia are abundant; in their initiation two branches take part. The oogonium is at first uninucleate but as it elongates the nucleus undergoes several divisions. In the meantime a second branch appears, usually borne on a narrower filament; it cuts off a uninu- cleate or occasionally binucleate terminal cell which applies itself to the middle of the oogonium, and the intervening walls disappear (fig. 33). Apparently, however, fertilization does not take place; the nu- cleus of the terminal cell is described as degenerating in situ while the oogonium undergoes septation and is transformed into a row of usually binucleate cells. Narrow vegetative hyphae grow up around this structure, and the perithecium is formed in the usual way. The archicarp of this species shows no importantpeculiarities but the terminal ^'S- 33- Penicillium vermiadatum , ^ It
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
