. Sexual reproduction and the organization of the nucleus in certain mildews. >T)ha with central body connected withchromatin. Fig. 25 a, 6.—Ascogonium with five cells; penultimate cell budding out in asco-genous h\phK; apical cell still connected to thick-walled antheridium. Fig. 26.—Median section of older ascocarp, showing sections of ascogenoushyphae, antheridium, etc.; peripheral cells swollen, in some cases in preparationfor pushing out as hj-phal branches. Fig. 27.—Median section of still older ascocarp, showing portion of ascogoniumand sections of multinucleated ascogenous h>phae
. Sexual reproduction and the organization of the nucleus in certain mildews. >T)ha with central body connected withchromatin. Fig. 25 a, 6.—Ascogonium with five cells; penultimate cell budding out in asco-genous h\phK; apical cell still connected to thick-walled antheridium. Fig. 26.—Median section of older ascocarp, showing sections of ascogenoushyphae, antheridium, etc.; peripheral cells swollen, in some cases in preparationfor pushing out as hj-phal branches. Fig. 27.—Median section of still older ascocarp, showing portion of ascogoniumand sections of multinucleated ascogenous h>phae. Fig. 28.—Section showing cells of ascogonium and ascogenous hj^phae at stagewhen latter become septate. Fig. 29 a, 6.—Sections showing the pushing out of the cells of the ascogenoushj-phse to form the young asci. Fig. 30.—Median section of ascocarp just after fusion of nuclei in the youngasci; two or more layers of cells around the asci, with dense content and thinwalls; peripheral cells on upper surface of ascocarp swelling out to form penicil-late cells. qu. 96 EXPLANATION OF FIGURES IN PLATES. Plate III.—Phyllactinia corvlea. Fig. 31.—Young ascus with two nuclei; central bodies facing each other. Fig. 32.—Slightly older ascus; chromatin strands more conspicuous. Fig. 33.—^Just before nuclear fusion in ascus. Lower nucleus lies above andpartially overlapping the other. Fig. 34.—Section of ascus with slice of one nucleus showing three chromatinstrands and sections of others. Fig. 35.—Early stage in fusion of nuclei; central body of upper nucleus haspushed ahead on the membrane of the lower nucleus, its chromatin system drawnout in long cone. Fig. 36.—Stage of fusion. Central bodies and chromatin of two nuclei side byside, but independent; nucleoli already combined in one. Fig. 37.—Chromatin systems overlapping, but distinct. Nucleoli in contact Fig. 38.—Stage just before the central bodies combine; nucleoli in this casestill separate. Fig. 39.
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtoncarnegie
