EXAMINATION & EXERCISES #2
FOR THE ASCOMYCOTA
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1. For each of the entries listed below, name the genus or a genus in the Ascomycota that "fits," and indicate the order to which
this genus belongs:
2. Complete the following classkfications:
For the following fill in the blanks or underline the correct statements:
3. Three representative genera of the Hemiascomycetes are: ___________________, ___________________,
4. Schizosaccharomyces octosporus is a (budding) (fission) yeast. It is (haplobiontic) (diplobiontic)
5. Venturia inaequalis incites a disease of ___________________ that is called ____________________.
This fungus has a (Monilia) (Graphium) (Polytrincium) (Fusicladium) (Oidium) (Spaceloma) imperfect
stage. The parasitic mycelium of V. inaequalis (is) (is not) confined to a subcuticular position. The sexual
process initiating the development of the perfect stage occurs (in spring) (in mid-summer) (in autumn) at high
latitudes and involves the union of (an antheridium) (a spermatium) with a trichogynous extension of an
6. If an unfamiliar cup fungus were encountered and examining it microscopically revealed that it had elongated
2-celled ascospores, it may be concluded with considerable confidence that this species belonged to the Sub-series
______________________________ of the Discomycetes.
7. An Oidium imperfect stage is typical of (Elsinoe) (Microsphaera) (Thielavia) (Myriangium) (Erysiphe)
8. In agar culture species of Taphrina may closely resemble (Endomyces) (Saccharomyces) (Schizosaccharomyces)
(Byssochlamys), both macro- and microscopically.
9. Asci arise from ascogenous hyphae in (Phyllactinia) (Byssochlamys) (Thielavia) (Endomycopsis) (Eurotium)
(Dipodascus) (Taphrina) (Neurospora) (Daldinia) (Higginsia) (Pyronema).
10. The yeast usually used in baking (is) (is not) a "sporogenous" yeast. The metabolic produce of the yeast that is
concerned in the leavening of bread dough is ______________________.
11. Saccharomyces cerevisiae (has) (does not have) the ability to hydrolyze starch. Therefore, a sterile
unhydrolyzed grain mash (will) (will not) provide a satisfactory source of carbohydrate for growth of this
years and/or for alcoholic fermentation.
12. With a substantial supply of sugar, minerals, etc., but a poor supply of oxygen, cells of Saccharomyces (will
soon die) (will thrive and multiply rapidly) (will live but will not bud very much).
13. In the pressence of an abundance of free oxygen, Saccharomyces cerevisiae tends to produce _____________and
___________________ as end products of its respiration. When the oxygen supply is low, alcohol and
__________________ are produced. The alcohol is (ethyl alcohol) (methyl alcohol) (butyl alcohol).
14. "Aspergillosis" in birds usually involves infection by (Aspergillus niger) (Aspergillus amsteledami)
(Aspergillus flavus) (Aspergillus fumigatus).
15. About (one fourth) (one half) (three fourths) of all known lichen fungi are assigned to the order Lecanorales.
Lichens whose thalli are of the upright, "shrubby" type are technically described as (crustose) (foliose)
16. Eremothecium and Ashbya are important fungi (because they incite disease in a crop plant) (because they have a
prominent role in decomposing organic matter in the soil) (because they produce an important antibiotic)
(because they are excellent sources of a certain vitamin).
17. Penicillin is obtained commercially from Penicillium ___________________. This species of Penicillium (has)
(is not known to have) a perfect stage.
18. The following genera belong to the Operculate Discomycetes: (Monilinia) (Leotis) (Helvella) (Urnula)
(Dibotryon) (Hypodermella) (Verpa) (Pyronema) (Mollisia) (Ascobolus).
19. Most higher Ascomycota apprently produce their asci through crozier formation. Fusion of two nuclei in the
young ascus was first observed by (de Bary) (Harper) (Dangeard) (Thaxter) (Seaver) about (1860) (1890)
20. The special cell division process whereby ascospores are delimited is called ___________________. This
process was first described by (de Bary) (Strasburger) (Harper) (Raper) (Thaxter) (Dodge) about (1850)
(1875) (1900) (1925). The unused cytoplasm that is left over in the ascus after spore delimitation is termed
(epiplasm) (periplasm). At inception, ascospores are (always) (almost always) unicellular, and (always)
(almost always) uninucleate.
21. Large unicellular sculptured ascospores occur in (Tuber) (Neurospora) (Taphrina) (Myriangium) (certain members of the
Pezizales) (many members of the Helotiales).
22. Mycelial cells of Taphrina are typically (uninucleate) (binucleate) (multinucleate). In T. deformans proasci are
formed (subcuticularly) (just under the epidermis) (scattered among the host cells near the surface of the
attacked host organ).
23. Daldinia and Xylaria belong to the order __________________. These two genera differ principally (in the
form of their stromata) (in the structure and shape of their ascospores) (in the substrates on which they grow).
24. The "Dermatophytes" that incite ringworm, athlete's foot and nail lesions in humans are believed to be related to
the Gymnoascaceae (because members of both groups are keratinophilic) (because of certain mycelial
peculiarities which are shared by the two groups).
25. In the following list place a check mark after any tiem that is found both in Venturia and in Neurospora: