The Cytology of Xenogloea Eriophori

SUMMARY

The application of Heidenhain's Hematoxylin and Trypan Blue staining techniques for the cytological study of Xenogloea eriophori suggests the following conclusions:

1.	Clamp-connections and probasidia are found abundantly on the hyphae inside of the leaf of Scirpus atrovirens instead of being restricted to the pustules on the leaf surface.
2.	Stages in meiosis in the probasidia of Xenogloea can be observed. The newly fused nucleus increases in size. Only one nucleolus is found in each nucleus after early prophase. There is evidence neither for the fusion of nucleoli during karyogamy, nor for the degeneration of one of the nucleoli. The nucleolus of Xenogloea is not solid; it is probably a sphere with a hollow center. Nucleoli seem to have disappeared in the diplotene stage and reappear in early telophase. The nuclear membrane cannot be distinguished at diplotene stage. Chromosome number in metaphase I is eight. No astral rays are found.
3.	The development of the basidia can be summarized as follows: Karyogamy occurs in the probasidium in the leaf and is soon followed by meiosis. Meiosis is completed in the probasidium in the leaf and a mature 4-celled basidium is formed there, or, for most of the probasidia, while the nucleus is in early prophase a hypha grows out at the basal or central portion of the probasidium, and grows toward the stoma. As soon as it reaches the stoma, a saccate structure is developed at its tip. The saccate structure increases in size; in the meantime, the nucleus in the probasidium in the leaf migrates through the hypha into the saccate structure in which meiosis is completed. A 4-celled basidium is thus formed in the pustules on the lower surface of the leaf. The basidiospores germinate by repetition, by budding or by producing one to four secondary spores, arranged, if more than one, in a fan-shaped pattern.