Fungi, Ascomycetes, Ustilaginales, Uredinales . a. mature ascocarp, xoo; b. <? development of archicarp,X300; d. older archicarp showing crowded nuclei, x 400 ; e mature archicarp withelaborately branched trichogyne, x 400;/. three ascogonial cells united by very largepores, X400. to ascogenous hyphae. Thus the oogonial region, though developmentallymulticellular, is for all practical purposes unicellular at maturity, and offersno greater difficulties in the way of fertilization than the oogonium ofPyroncma itself. The branched character of the trichogyne is exceptional among Disco-mycetes
Fungi, Ascomycetes, Ustilaginales, Uredinales . a. mature ascocarp, xoo; b. <? development of archicarp,X300; d. older archicarp showing crowded nuclei, x 400 ; e mature archicarp withelaborately branched trichogyne, x 400;/. three ascogonial cells united by very largepores, X400. to ascogenous hyphae. Thus the oogonial region, though developmentallymulticellular, is for all practical purposes unicellular at maturity, and offersno greater difficulties in the way of fertilization than the oogonium ofPyroncma itself. The branched character of the trichogyne is exceptional among Disco-mycetes ; it might, no doubt, facilitate the establishment of contact with an iv] PEZIZALES in attached antheridium if the latter developed at a distance. But branchingmight also be regarded as a secondary or vegetative development, appearingafter normal fertilization had i ea led to occur. The presence of pores in the transverse septa of the trichogyne suggeststhat the function of that organ in relation to an antheridium has onlyrecently been Fig. 67. Humariagranulata Quel.; young archicarp, X320; after Blackmail ami Fraser. The ascogenous hyphae contain many nuclei irregularly arranged. Asciin- formed in the usual way; their nuclei show about eight chromosomesin the first division. Owing to the small size of the nuclei further cytologicaldetails have not been studied in this species. 112 DISCOMYCETES [ch. Humariagranulata is a common red or orange coprophilous form. Thearchicarp develops as a side branch from an ordinary hypha. The apicalcell of this branch increases in size and becomes spherical, forming theoogonium (fig. 67); it contains large numbers of well-marked nuclei. Whenit is full grown the oogonial nuclei fuse in pairs (fig. 68 a), and the fusionnuclei pass into the ascogenous hyphae (fig. 68 fi). There is no sign of eithertrichogyne or antheridium.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfungi, bookyear1922
