Development of the Perithecium in Aspergillus Fischeri Wehmer, with a Description of Crozier Formation

Aspergillus Fischeri Wehmer is one of three ascosporic species of Aspergillus recently obtained in our laboratory on tea leaves by Mrs. Ruth Ellis Allen. The writer obtained the fungus in culture from Mrs. Allen, whose paper surveying the three abovementioned species is being prepared for publication. Aspergillus Fischeri Wehmer is an ascosporic species occurring in the A. fumigatus group. We are indebted to Dr. Kenneth Raper for the identification of this species. The present paper describes the morphology and cytology of perithecial development in Aspergillus Fischeri, with a detailed account of crozier formation. Professor John N. Couch first discovered the presence of croziers in this fungus and found that he could best demonstrate them by dissecting the young perithecia under the microscope, rather than by preparing microtome sections. With this in mind, the writer has developed, and will later describe, a rather simple method for preparing slides for cytological study of crozier formation in Aspergillus. Apparently, croziers have been overlooked in many Ascomycetes because the investigator has relied too much upon sectioned material. Dangeard (3), in 1907, described perithecial development in a species which he identified as Aspergillus fumigatus Fresenius, but did not observe crozier formation here. Since DeLamater (4) found that croziers were formed in Arachniotus, one of the lowest of the Euascomycetes, it is not at all surprising that they are found in Aspergillus. Emmons (5, 6) has already reported