. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. « «\ 4 ^ ^ > i 1938] True: Gall Development on Pinus Sylvestris 41. Fia. 6, A. A portion of the dome of the peridium with cells drawn in outline. B. Portion of the bases of aecial spore chains showing binucleate and trinueleate condition. C. Young aeciospores, some binucleate and some trinueleate. D. An apparent binucleate condition in a cell of a vegetative hypha. E. Hyphae and haustorium in the cortex. Note the effects of shrinkage upon the nucleus at its poin
. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. « «\ 4 ^ ^ > i 1938] True: Gall Development on Pinus Sylvestris 41. Fia. 6, A. A portion of the dome of the peridium with cells drawn in outline. B. Portion of the bases of aecial spore chains showing binucleate and trinueleate condition. C. Young aeciospores, some binucleate and some trinueleate. D. An apparent binucleate condition in a cell of a vegetative hypha. E. Hyphae and haustorium in the cortex. Note the effects of shrinkage upon the nucleus at its point of contact with the haustorium. The usual number of nuclei in the vegetative cells and of those making up sterile portions of the wefts is 1, and, while 2 have been exceptionally found in vegetative cells (Fig. 6, D), it seems likely that they do not indicate the initiation of a distinct stage in the life cycle. A 2-, 3- and, exceptionally, 4-nucleate condition arises in the basal cells of the enlarged hyphae that cut off the young aecial spore chains (Fig. 6, B), and the young aeciospores are in turn usually binucleate but often possess 3 (Fig. 6, C) and at times 4 nuclei. The nuclei in maturing spores appar- ently become grouped, but no actual fusion has been observed. The young germ tubes, however, often appear to have 2 or more nuclei per cell, but only 1 has been observed in each cell at the time of host penetration. Until further cytological studies can be made upon this organism, the interpreta- tion of these nuclear phenomena would appear hypothetical. Dodge and Adams (4) found that of a collection of Cronartium querciium (C. cerebrum) galls on Pinus rigida from New Jersey, some produced only. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original University of Pennsylvania. Botanical Laboratory; Univer
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