. Black rot, leaf spot and canker of pomaceous fruits. Black rot; Leaf spots; Canker (Plant disease); Apples. Fig. 19. asci and paraphyses of physalospora cydoniae Camera lucida draw- ing of asci and paraph- yses, showing structure of the latter and typical arrangement of asco- spores in the ascus walled. The inner, thin-walled layer is of very uniform diameter. In cases in which the perithecium is depressed, the outer layer is reduced at the base and is from one to three pseudo-cells in thickness, whereas the lateral outer walls are from two to five layers of pseudo-cells in thickness. The os
. Black rot, leaf spot and canker of pomaceous fruits. Black rot; Leaf spots; Canker (Plant disease); Apples. Fig. 19. asci and paraphyses of physalospora cydoniae Camera lucida draw- ing of asci and paraph- yses, showing structure of the latter and typical arrangement of asco- spores in the ascus walled. The inner, thin-walled layer is of very uniform diameter. In cases in which the perithecium is depressed, the outer layer is reduced at the base and is from one to three pseudo-cells in thickness, whereas the lateral outer walls are from two to five layers of pseudo-cells in thickness. The ostiole appears as a narrow passage in the papilla, the walls of which show the same distinct layers as those just described for the sides and base of the perithecium. The asci, with the interspersed paraphyses, usually fill the cavity of the perithecium. Arnaud (1912 :11) states that in general the paraphyses are formed by rows of cells which in the ma- ture peri- t h e c i u m are sepa- rated one from an- ot h e r in the form of distinct fil- aments. He says that in cer- tain cases, however, the paraphyses remain aggluti- nated by their walls and appear in section like rows of cellular cavities, as in Cucur- bitaria (C. Spartii and other species). He explains that if the rows of cells are not very numerous the existence of the paraphyses may become un- certain. Arnaud finds this the case with Physalospora Cydoniae. The writer, how- ever, has not observed this condition of the paraphyses; to him thev apoear distinct The upper series represents variations as found on apple bark. The lower series shows variations from bark of witch- and IlOn-Septate (Fig. io). hazel . ' The asci are abundant; asci crushed from one perithecium are shown in Plate xiii, 2. They are usually clavate, although they sometimes tend to be cylindrical, measuring Fig. 20. ASCI OF PHYSALOSPORA CYDONIAE FROM DIFFERENT HOSTS. Please note that these images are extracted from scanned page images that may have bee
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectblackro, bookyear1916
