Fungi, Ascomycetes, Ustilaginales, Uredinales . nea cretea and the Ascoboli, where the coiled and septate archicarp isoften still functional. A very common initial organ in forms with embedded perithecia is theshort filament of cells sometimes known as Woronins hypha (fig. 103). Thecells are large and contain well-marked nuclei and lie in a nest of small-celled vegetative mycelium. Woronins hypha has been found among theHypocreales mNectria and among the Sphaeriales in Xylaria an&Hypoxylon; it remains to be shown whether it still functions. It may haveoriginated from the simple archi-carps of
Fungi, Ascomycetes, Ustilaginales, Uredinales . nea cretea and the Ascoboli, where the coiled and septate archicarp isoften still functional. A very common initial organ in forms with embedded perithecia is theshort filament of cells sometimes known as Woronins hypha (fig. 103). Thecells are large and contain well-marked nuclei and lie in a nest of small-celled vegetative mycelium. Woronins hypha has been found among theHypocreales mNectria and among the Sphaeriales in Xylaria an&Hypoxylon; it remains to be shown whether it still functions. It may haveoriginated from the simple archi-carps of the Lower Pyrenomy-cetes or by reduction from formswith a multicellular its final disappearance wereach such completely apogamousspecies as those of Cordyceps andClaviceps. (iii) A quite distinct type ofprimordium has been describedin Strickeria, Sporormia and Pleo-spora; in these cases the asco-genous and vegetative filamentsarise from a common initial cellwhich divides not only transverse-ly, but longitudinally, forming a. Fig 10+. Strickeria sp.; initial cells of ascocarps;alter Nichols. compact tissue (fig. 104). Other hyphae may anastomose with this mass,or it may give rise alone to the whole fructification. Possibly some sugges-tion of its origin may be found in the peculiar, but apparently normallyfertilized oogonium of Lcptosphaeria. The Pyrenomycetes do not appear to have given rise to any higherforms, and have themselves a greater vegetative development than any otherAscomycetes. They may be subdivided as follows: Wall of perithecium differentiated from stroma; perithecium wall and stroma, if present, soft in texture, either colourless or light coloured HYPOCREALES. perithecium wall and stroma, if present, firm, leathery or brittle, dark in colour Perithecium always sunk in a stroma from the tissue ofwhich its wall is not differentiated ; colour of stromablack or dark brown DOTHIDEALES. Minute, external parasites on insects, perithecium b
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
