. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. Ill] EXOASCALES 93 mother-cell during development. Two nuclei can frequently be recognized in the cells of the fertile mycelium, and the young ascus, in all investigated cases, is binucleate. The two nuclei fuse, the fusion nucleus undergoes three successive divisions and eight spores are formed (fig. 48). In many species budding of the ascospore takes place, so that the mature ascus contains numerous minute conidia (fig. 50) by means of which the fungus is distributed. The Exoascales include the single family Exoascaceae; with this is so
![. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. Ill] EXOASCALES 93 mother-cell during development. Two nuclei can frequently be recognized in the cells of the fertile mycelium, and the young ascus, in all investigated cases, is binucleate. The two nuclei fuse, the fusion nucleus undergoes three successive divisions and eight spores are formed (fig. 48). In many species budding of the ascospore takes place, so that the mature ascus contains numerous minute conidia (fig. 50) by means of which the fungus is distributed. The Exoascales include the single family Exoascaceae; with this is so Stock Photo](https://c8.alamy.com/comp/RDTP3J/fungi-ascomycetes-ustilaginales-uredinales-fungi-ill-exoascales-93-mother-cell-during-development-two-nuclei-can-frequently-be-recognized-in-the-cells-of-the-fertile-mycelium-and-the-young-ascus-in-all-investigated-cases-is-binucleate-the-two-nuclei-fuse-the-fusion-nucleus-undergoes-three-successive-divisions-and-eight-spores-are-formed-fig-48-in-many-species-budding-of-the-ascospore-takes-place-so-that-the-mature-ascus-contains-numerous-minute-conidia-fig-50-by-means-of-which-the-fungus-is-distributed-the-exoascales-include-the-single-family-exoascaceae-with-this-is-so-RDTP3J.jpg)
Image details
Contributor:
The Book Worm / Alamy Stock PhotoImage ID:
RDTP3JFile size:
7.1 MB (390.4 KB Compressed download)Releases:
Model - no | Property - noDo I need a release?Dimensions:
1834 x 1362 px | 31.1 x 23.1 cm | 12.2 x 9.1 inches | 150dpiMore information:
This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.
This image could have imperfections as it’s either historical or reportage.
. Fungi, ascomycetes, ustilaginales, uredinales. Fungi. Ill] EXOASCALES 93 mother-cell during development. Two nuclei can frequently be recognized in the cells of the fertile mycelium, and the young ascus, in all investigated cases, is binucleate. The two nuclei fuse, the fusion nucleus undergoes three successive divisions and eight spores are formed (fig. 48). In many species budding of the ascospore takes place, so that the mature ascus contains numerous minute conidia (fig. 50) by means of which the fungus is distributed. The Exoascales include the single family Exoascaceae; with this is sometimes associated the Ascocorticiaceae containing the saprophytic. Fig. 50. Taphrina aurea (Pers.) Fr.; mature asci, x 500. genus Ascocorticium with five known species. The asci of Ascocorticmin, like those of the Exoascaceae, are cylindrical in form, parallel in arrange- ment and quite unprotected. It is open to question whether the parallel arrangement of the asci in the Exoascaceae has any phylogenetic significance or is not rather the result of their development on the surface of the carpel or leaf The cylindrical form of the ascus, however, does not suggest a primitive group. It may perhaps be inferred that the Exoascaceae are reduced forms derived from one of the phyla with protected asci; there does not appear at present to be any clue to their probable ancestry. The same is true of the Ascocorticiaceae, of the development of which even less is known. Exoascaceae The classification of the Exoascaceae, and especially the separation of the two principal genera, Ezoascus and Taphrina, has been based on a variety of different characters including the form of the ascus, the develop- ment or not of conidia from the ascospores, the annual or perennial character of the mycelium and the presence or absence of a stalk cell. Boudier defines Exoascics as having asci usually octosporous and usually provided with a basal cell; Taphrina as having asci usually polysporous, sometimes pr