DIVERSITY OF LIFE
PHYLUM ASCOMYCOTA

EUKARYA>OPISTHOKONTA>UNIKONTA>FUNGI>DIKARYA>ASCOMYCOTA

The Ascomycota (as-ko-mi-KO-ta) is derived from two Greek roots that mean wineskin or bladder (aski -ασκί); and fungus (mykes -μύκης).  The reference is to the structure (ascus) within which the sexual meiospores are formed.

INTRODUCTION TO THE ASCOMYCOTA

The ascus-bearing fungi include a very diverse and economically-important collection of organisms.  Asci (Figure A) and ascocarps (Figure B), the structures that bear the asci, are among the important structural themes in this phylum.  Asci contain the sexual meiospores, which may be agents of dispersal, but most taxa disperse themselves asexually by means of conidiospores contained on conidia (Figure C).  The phylum itself is extraordinarily diverse formed of free-living, parasitic, and symbiotic taxa (Figures D-T).  Many are parasites of agricultural plants and cause diseases like: apple scab, apple bitter rot, brown stone rot, strawberry stem rot, etc.  Some, like Endothia parasitica, have by their introduction altered the Eastern Deciduous Forest in North America by the effective elimination of one of its dominant plants, the American Chestnut (Castanea dentata).  Similarly, American Elms (Ulmus americana) have disappeared due to the introduction of another ascomycete that causes Dutch Elm Disease.  

Ascomycete-caused diseases are not restricted to plants.  For example, skin ailments (e.g. ringworm, athlete's foot), and histoplasmosis, a pneumonia-like disease, are caused by ascomytogenous fungi.  Household molds (toxic molds, black molds, and green molds) tend to be from this phylum, though many have lost the ability to produce sexual spores.  Ergot, a disease brought on by ingesting rye infected with Claviceps purpurea, causes hallucinations and uncontrolled contractions of certain muscles, especially the uterus.  The active agent in ergotized grain seems to be a compound similar to LSD.

All ascomycetes are not dangerous or detrimental.  Truffles and morels produce much-prized edible ascocarpsYeast (Saccharomyces and related taxa) is perhaps the most economically-important fungus of all and is responsible for the alcoholic fermentation of beer, wine, etc. as well as the fermentation necessary for the production of leavened bread.

Some species of the Orbiliomycetes are associated with dry wood and are the causative agents of dry rot. These thrive in the xeric environments of dry dead wood on a tree (where they can be exposed to drying winds and sun) or the semi-arid soil associated with plants like Yucca. However, when the hyphae of their sparse mycelia come into contact with nematodes, they begin to elaborate hyphal loops, which function as nematode traps.  When a nematode sticks its head into a snare, the hydrostatic pressure of the hyphal loop increases suddenly, and the worm is caught.  The fungus then elaborates a feeding haustorium into the nematode and quickly digests the animal. The fungus, with the added nutrition from the nematode, elaborates conidia for dispersal.  Not only do they lead a double life as wood eaters and nematode trappers, but some have lost the ability to make asci.  The most well-known nematode-eating fungus, Arthrobotrys, is the anamorph (asexual form) of some taxa within the sexual genus Orbilia.  Thus, these same fungi can consume the trim wood on my garden shed door, recycle wood and its elements in the brush pile at the bottom of my yard, and consume soil nematodes in the garden bed where I grow tomatoes.  Clearly, the benefits to me far outweigh the costs.

Many species of the ascomycetes perform ecological functions that are quite valuable in the long run.  Indeed, the environmental role of most ascomycetes cannot be overstated.  Apart from their roles as "decomposers", many of them enter into symbiotic relationships with plants to form a fungus-plant mycorrhizal associations.  Similar fungus chimeras include the lichens, most of which have an ascomycete as the mycobiont.

The typical ascomycete life cycle involves the association of haploid, monokaryotic branched filaments.  In the case of morel (Morchella), hyphae of two compatible mating types associate and begin to weave the ascocarp.  Then, in the hymenial layer, each filament has cells that enlarge.  The functional female grows a long structure called a trichogyne that fuses with an enlarged cell in the compatible filament.  The result is the emergence of a filament that remains haploid with two distinct nuclei (dikaryotic).  As it divides, the terminal end makes a crook (called a crozier) that sequesters one of the nuclei to insure that each daughter cell has the full complement of haploid nuclei.  This dikaryon is short-lived and after a few cell divisions leads to the development of the ascus, within which the haploid nuclei fuse and then undergo meiosis to form the ascospores on the surface of the ascocarp.  

One of the oddest members of this phylum is Laboulbenia, an obligate parasite of insects, especially beetles, with a distinctive non-mycelial and determinate growth pattern. The fungus body, the receptacle, attaches to the host by a basal cellular holdfast and a single, simple haustorium penetrates the insect.  Lateral filamentous appendages and one or more sessile or stalked perithecia arise on the receptacle after feeding on the insect.  The ascus wall deliquesces (begins to gelatinize) prior to spore discharge. 

SYSTEMATICS OF THE ASCOMYCOTA

The taxonomy of the Ascomycota has been in flux for some time ( e.g. Alexopoulos and Mims 1979, Bold et al. 1987, and Scagel et al. 1984).  First, the practice of separating the lichens and imperfect fungi (those that do not exhibit sexual reproduction) was abandoned and more natural taxonomic systems began to appear.  This trend can be seen in the systems of Margulis and Schwartz (1982, 1988, and 1998).  Then, Nishida and Sugiyama (1994) discovered a distinct group that they called the Archiascomycetes according to their SSU rRNA analysis of fungi. Thus, they and others including Liu et al. (1999), defined the Ascomycota as having 3 classes: Archiascomycetes, Saccharomycetes, and the Euascomycetes.  Both the Saccharomycetes and the Euascomycetes groups seemed to be well defined and monophyletic.  The "Archiascomycetes" seemed to be paraphyletic and comprised the broad grouping from which the other two groups sprang.  We feel that the diversity of the Ascomycota is too great to be reflected in a system of 3 classes.  Thus, we have adopted the system of Eriksson et al. (2001) which has 3 subphyla and 14 classes.  The analysis of Lutzoni et al. (2004) confirms the monophyly of the Ascomycota but calls into question the monophyly of some of the Taphrinomycotina.  Adl et al. (2005) seem to separate the ascomycotes into four taxa at the level of Taphrinomycotina (which we interpret as 4 subphyla).  Thus, the system of Eriksson et al. (2001) likely will be modified.

asci-humboldt.gif (11070 bytes)

A. Asci of Peziza with ascospores (opaque linear structures)

ascocarps-bold.jpg (106409 bytes)

B. The types of ascocarps found in the Ascomycota.

conidium-vbi.jpg (91523 bytes)

C. An SEM micrograph illustrating the structure of an ascomycete conidium.

neolecta-uoguelph.jpg (45775 bytes)

D. The ascocarps of Neolecta, a symbiont (parasite?) of spruce.

Pneumocystis_BAL_cysts-cdc.jpg (37595 bytes)

E. Spores of Pneumocystis from a lung tissue of a person who was immune compromised by HIV. 

schizosaccharomyces-umassmed.jpg (12213 bytes)

F. Schizosaccharomyces, a non-budding yeast.

Taphrina_deformans_asci_tjv-wisc.jpg (31281 bytes)

G. Asci of Taphrina are scattered over the host tissue rather than being united into an ascocarp.

saccharomyces-bath.gif (107983 bytes)

H. An SEM image of Saccharomyces showing a developing bud and bud scars.

arthonia-pnl.jpg (28134 bytes)

I. Arthonia, an ascomycete fungus in lichenized form.

fruit_sootymold-chaetothyrium-dost.jpg (7888 bytes)

J. Sooty mold caused by Chaetotherium.

capnodium-perithecium-ncsu.jpg (11447 bytes)

K. Capnodium forming a perithecium on Pinus.  This is the causative agent of sooty mold on pine.

venturia-ASCOcarp-uottawa.gif (94495 bytes)

L.  Perithecia of Venturia in the leaf tissue of apple (causing apple scab).

eurotium-herbariorum-schimmel.gif (790065 bytes)

M. An SEM micrograph of a Eurotium cleistothecium.  This is the perfect stage of the mold that produces aflatoxins in peanuts and grain.

Cladonia-macilenta-uvic.jpg (178650 bytes)

N. Cladonia, a common lichenized fungus known as British Soldier.

O. The cleistothecium of Microsphaera, the agent responsible for powdery mildew on lilac leaves.

Peziza-micropus-uni-griefswald.jpg (42438 bytes)

P. Apothecia of Peziza.

morchella-umn.jpg (49689 bytes)

Q. Ascocarps of Morchella, a prized delicacy for mushroom pickers.

claviceps-unsa.jpg (48189 bytes)

R. Perithecia of Claviceps growing in rye.  This is the agent responsible for ergot.

neurospora-perithecium-berkeley.gif (86961 bytes)

S. An SEM micrograph of the perithecium of Neurospora.

laboulbenia-bsu.jpg (29459 bytes)

T. The receptacle of Laboulbenia attached to the body of an ant.

Images taken from:
A: http://www.humboldt.edu/~dll2/bot105/fungi/ascos.htm
B: Bold et al. (1987)
C: http://staff.vbi.vt.edu/pathport/pathinfo_images/Aspergillus_flavus/23293C.jpg
D: http://www.uoguelph.ca/~gbarron/SAC%20FUNGI/ascokey.htm
E: http://www.dpd.cdc.gov/dpdx/HTML/Pneumocystis.asp?body=Frames/M-R/Pneumocystis/
F: http://www.umassmed.edu/bmp/graphics/rhindfig1.jpg
G: http://botit.botany.wisc.edu/images/332/Ascomycota/Hemiascomycetes/
H: http://www.bath.ac.uk/bio-sci/wheals2.gif
I: http://www.pnl.gov/ecology/Gallery/lichens/arun.html
J: http://www.min.pcarrd.dost.gov.ph/pest/fruit/fruit_sootymold.html
K: http://www.cals.ncsu.edu/course/pp318/profiles/fdc/fdc.htm
L: http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm
M: http://schimmel-schimmelpilze.de/download-1/eurotium-herbariorum.gif
N: http://web.uvic.ca/ail/bibliography.html
O: http://sorrel.humboldt.edu/~dll2/bot359/htmfiles/erysipha/microsp1.gif
P: http://www.uni-greifswald.de/~mycology/gallery/Seiten/Peziza%20micropus.htm
Q: http://fungi.umn.edu/gallery/725058a.jpg
R: http://www.pmf.unsa.ba/biologija/talofiti/asco6b.jpg
S: http://pmb.berkeley.edu/~glass/Glasslab_site/
T: http://www.bsu.edu/classes/ruch/msa/blackwell/9-4.jpg

SYNOPTIC DESCRIPTION OF THE ASCOMYCOTA

The following description comes from Alexopoulos and Mims (1979), Alexopoulos et al (1996), Bold et al. (1987), and Scagel et al., (1984).

I. SYNONYMS: ascomycetes, sac fungi.

II. NUMBER: >15,000 species.

III. PHYLUM CHARACTERISTICS:

A. ASEXUAL REPRODUCTION:  Conidia.

B. SEXUAL REPRODUCTION:  Ascospores produced within an ascus and often enclosed within an ascocarp. Nuclear fusion followed by meiosis (and usually a mitosis) to produce 8 ascospores in an ascus.  Distinctive gametangia and stages of ascospore formation.

C. VEGETATIVE HYPHAE:  Haplophase dominant; dikaryophase produces ascogenous hyphae and ascus mother cells.

D. CELL WALLS: Chitin and glucan.

E. ECOLOGY: These are fungi that are free-living saprobes or parasites.  Some of them make chimeroid entities like mycorrhizal associations and lichens

HIERARCHICAL CLASSIFICATION OF THE ASCOMYCOTA

This system is a modification of Eriksson et al (2001) which has 3 subphyla and 14 classes.

SUBPHYLUM TAPHRINOMYCOTINA = CLASS ARCHIASCOMYCETES 

This is the group that Nishida and Sugiyama (1994) called the class Archaeascomycetes.  I have raised it to subphylum level according to the system of Ericksson (2000) who claims that they are the sisters to all of the other Ascomycota, and they appear to be the groups from which the other Ascomycotes arose.  However, the following classes differ from each other structurally and, according to Ericksson (2000), on the basis of their SSU rRNA sequences.    Thus, the diversity of the group of four classes really indicates that they are defined by exclusion from the well-defined and natural groupings: Saccharomycotina and Pezizomycotina.  Also, I am troubled by their apparent primitiveness.  All of these taxa (except the fission yeasts) are parasites and, therefore, may only appear to be primitive through reduction.  Clearly, the book is not closed on the taxonomy of the Ascomycota.

CLASS NEOLECTOMYCETES

These are fungi that produce large fruiting bodies (ascocarps up to 9 cm tall).  The ascogenous hyphae do not have crosiers.  The asci open by a slit.  The ascospores germinate to form yeast-like conidia.  The mycelia and fruiting bodies are associated with spruce roots and may be parasitic.  

ORDER NEOLECTIALES

Neolecta 

CLASS PNEUMOCYSTIDOMYCETES

These live as parasites in the alveoli of certain vertebrates and, therefore, are of significant medical importance.  They grow as yeasts that divide by fission (not budding).  They fuse to form asci of 8 banana-shaped ascospores.  

ORDER PNEUMOCYSTIALES

Pneumocystis

CLASS SCHIZOSACCHAROMYCETES  = OCTOSPOROMYCES

These are the fission yeasts.  They fuse to form asci of four or eight ascospores.  They live as saprobes in fruit juice.  

ORDER SCHIZOSACCHARIALES

Schizosaccharomyces

CLASS TAPHRINOMYCETES

Biotrophic parasites of seed plants and ferns causing galls, leaf curls, deformed fruits and witches brooms. Intercellular or subcuticular dikaryophase mycelium in parasitic phase with terminal chlamydospores or ascogenous cells, each forming a single ascus in a hymenium-like layer; after nuclear fusion and mitosis, ascogenous cells often divide to give a basal stalk cell with ascus at the apex; ascospores may bud within ascus so that it appears multispored; saprotrophic phase of budding monokaryotic cells; can be cultured in the yeast state.  

ORDER TAPHRINALES)

Taphrina, Protomycetes.

SUBPHYLUM SACCHAROMYCOTINA = HEMIASCOMYCETES

These are the budding yeasts.  Vegetative phase unicellular yeast-like or filamentous; asci one-walled, naked, not borne on ascogenous hyphae, produced singly, following karyogamy; no ascocarps.  

CLASS SACCHAROMYCETES

ORDER SACCHAROMYCETALES = ENDOMYCETALES

Saccharomyces, Dipoascus.

SUBPHYLUM PEZIZOMYCOTINA

These comprise most of the ascomycota.  The organisms form mycelia that make ascocarps (ascus-bearing structures also called ascomata) with hymenia.  Some of the taxa are lichenized (enter into a symbiotic relationship with algae to form lichens).  Some of the taxa have lost the ability to undergo meiosis and, although they might fuse, they can not produce ascospores or asci.  Such taxa were once called the Fungi Imperfecti or Deuteromycota.  Such a distinction is decidedly artificial.  On the other hand, symbiotic entities like lichens do not easily fit into a natural system unless the fungal symbiont (mycobiont) is given complete preference.  To be consistent with current fungal taxonomic systems, I will include the lichenized fungi in this system and describe the lichens in a separate page.  This subphylum follows that of Ericksson (2000), but I have added a 9th class, Laboulbeiomycetes, a group of uncertain status in Ericksson's system.

CLASS ARTHRONIOMYCETES 

This class appears to be monophyletic. Most of them are lichenized and produce asci with double walls and slits.  The asci elongate to a rostrum when discharging spores.   The ascocarps are apothecia with a naked hymenium.  

ORDER ARTHRONIALES

Arthonia, Chrysothrix, Melaspilea, Roccella, Arthrophacopsis.

CLASS CHAETOTHYRIOMYCETES

This class appears to be monophyletic. Most species are saprobes on vascular plants, dead wood, lichens, etc.  Some are human pathogens.  The ascocarps are small perithecia that contains paraphyces.  

ORDER CHAETOTHYRIALES

Chaetothyrium, Capronia, Adelococcus, Verrucaria.

CLASS DOTHIDIOMYCETES 

Typically, these form bitunicate asci within perithecia (members of the order Patellariales produce apothecia).  The asci usually are associated with paraphyses-like structures (pseudothecia).  The spores are septate.  This class and the Chaetothyriomycetes corresponds to Loculoascomycetes in some earlier systems and is often referred to as "bitunicate ascomycetes".  Five orders are recognized in this system (after Ericksson, 2000). Some families will probably have to be transferred to the Chaetothyriomycetes when more molecular data are available.

ORDER CAPNODIALES

Capnodaria, Capnodium, Achaetobotrys, Antennulariella, Coccodinium, Metacapnodium.

ORDER DOTHIDIALES

Asci ovoid, club-shaped or cylindrical, grouped in small locules without pseudoparaphyses in pseudothecia; pseudothecia separate or grouped on or in stroma; ascospores usually uniseptate.

Dothidea, [Mycosphaerella, Guignardia both incertae sedis].

ORDER HYSTERIALES

On dead woody branches and bare wood; with distinct boat-shaped, carbonaceous pseudothecia opening by longitudinal slit and appearing apothecium-like when moist.

Hysterium.

ORDER MYRIANGIALES

Mostly tropical or subtropical, epiphytes, parasites or hyperparasites on fungi or scale insects on living leaves and stems; asci globose, scattered individually throughout ascocarp.

Myrangium, Elsinoe.

ORDER PATELLARIALES

Asci in apothecia.

Patellaria

ORDER PLEOSPORALES

Asci long, cylindrical, separated by pseudoparaphyses in relatively large, uniloculate, usually solitary pseudothecia; ascospores commonly phragmosporous or dictyosporous, pigmented.

Venturia, Delitschia, Leptosphaeria, Lophiostoma, Melanomma, Montagnula, Phaeosphaeria, Phaeotrichum, Pleospora, Sporormia, Teichospora.

CLASS EUROTIOMYCETES

This class appears to be monophyletic. Two orders are accepted. The Elaphomycetaceae form a monophyletic group with Eurotiales and are not treated as a separate order, but should perhaps be placed in a separate suborder in Eurotiales.  Asci are small, evanescent and are produced at different levels within the ascocarp which may vary from a loose weft of hyphae bearing asci to a well organized structure with a definite wall; the ascocarp is often enclosed by a cleistothecium (but osteolate in some); conidia common; widespread and often associated with seeds, soils, and as animal parasites. "The blue and green molds".  Some like Aspergillus and Penicillium are form-taxa.  That is, sexual structures are not known.  The class has 2 orders.

ORDER EUROTIALES

Eurotium, Eupenicillium.

ORDER ONYGENIALES

Gymnoascus, Eremascus, Onygena, Ascosphaera, Arthroderma

CLASS LECANOROMYCETES

This class contains most of the lichenized fungi.  Most produce asci in apothecia with a naked hymenium.  Asci usually thin-walled with a thicker wall at the distal end.  Dehiscence is rostrate.  This class  is used for most of the discolichens, but it is not strongly supported in phylogenetic analyses.  This is a large and diverse class of 5 orders and 500 genera.

ORDER AGYRIALES

Agyrium, Lithographa, Anamylopsora, Elixia.

ORDER GYALECTALES

Coenogonium, Gyalecta.

ORDER LECANORALES

Acarospora, Hymenelia, Anzia, Arctomia, Anthroraphis, Biatorella, Calicium, Calycidium, Catillaria, Cetradonai, Cladonia, Coccocarpia, Collema, Crocynia, Dactylospora, Gypsoplaca, Haematomma, Arctopeltis, Lecanora, Lecidea, Loxospora, Megalaria, Macarea, Miltidea, Micoblastus, Ophioparma, Pachyascus, Pannaria, Parmelia, Physcia, Porpidia, Psora, Ramalinia, Rhizocarpon, Sphaerophorus, Stereocaulon, Lobaria, Nephroma, Peltigera, Placynthium, Fuscidea, Letrouitia, Teloschistes.

ORDER LICHINALES

Gloeoheppia, Heppia, Lichina, Peltula.

ORDER PERTUSARIALES

Megaspora, Pertusaria.

CLASS LEOTIOMYCETES

They have thin-walled asci that are inoperculate.  The mildews are part of this class (as indicated by molecular studies).  Most produce apothecia (the mildews produce reduced cleistothecia).

ORDER CYTTARIALES

Cyttaria.

ORDER ERISIPHALES

Biotrophic parasites; ascocarps with 1 to several oval-shaped to club-shaped explosive asci; ascospores unicellular, colorless; chains of conidia arising in basipetal succession from mother cell on superficial colorless mycelium; penetration of host by haustoria confined to epidermal cells. "Powdery mildews."

Erysiphe, Microsphaera, Uncinula.

ORDER HELIOTIALES (HELOTIALES)

Asci inoperculate in distinct hymenium in apothecia of varying form; mostly saprotrophic but with a few plant pathogens.

Monilinia, Bulgaria, Dermea, Geoglossum, Hemiphacidium, Hyaloscypha, Leotia, Loramyces, Phacidium, Rustroemia, Sclerotinia, Vibrissea, Ascocorticium.

ORDER RHYTISMATALES

Ascodichaena, Cryptomyces, Cudonia, Rhytisma.

ORDER THELEBOLALES

Thelebolus.

CLASS ORBILIOMYCETES

This class contains dry rot fungi, as well as taxa that feed on other plants.  When in the presence of nematodes, some will elaborate capture mechanisms with which they can significantly reduce the populations of soil nematodes.  Arthrobotrys is the anamorph (asexual form) of small cup fungi, in the genus Orbilia.

ORDER ORBILIALES

Orbilia, Hyalorbilia

CLASS PEZIZOMYCETES

Thin-walled asci operculate in distinct hymenium.  Most produce apothecia of varying shapes, large to minute; saprophytic on soils, dung, wood and plant debris.  Others (truffels) produce subterranean (hypogeal)  ascocarps that are modified apothecia in which the acsi have become inoperculate.  This large class has a single order (PEZIZALES)

ORDER PEZIZALES

Anthracobia, Ascolobus, Ascodesmis, Caloscypha, Carbomyces, Gyromitra, Glaziella, Helvella, Karstenella, Acervus, Pyronema, Sphaerosoma, Peziza, Morchella, Rhizinia, Sarcoscypha, Sarcosoma, Tuber.

CLASS SORDARIOMYCETES

These have unitunicate asci in perithecia.  The asci open by a pore  This assemblage is supported by SSU rRNA as a natural group.  The 8 orders are distributed among 3 subclasses: Hypocreomycetidae, Xylariomycetidae, and Sordariomycetidae.  This is a large and diverse class of nearly 800 genera.

ORDER HALOSPHAERIALES

Halosphaeria.

ORDER HYPOCREALES

Perithecial fungi with unitunicate asci; perithecia usually in a well-developed stroma which is usually light-colored; asci are long and cylindrical, with a thickened apex; 8 ascospores which are filiform, hyaline, septate and break apart easily; mainly parasitic on grasses, insects, spiders and other fungi.

Bionectria, Melanospora, Claviceps, Hypocrea,Nectria, Niesslia.

ORDER MICROASCALES

Chadefaudiella, Microascus.

ORDER BOLINIALES

Endoxyla, Catabotrys.

ORDER DIAPORTHALES

Melanoconis, Valsa.

ORDER OPHIOSTOMATALES

Kathistes, Ophiostoma.

ORDER SORDARIALES

Perithecia are ostiolate with persistent, unitunicate asci; asci usually embedded in a stroma which may be composed of both host and fungus tissue or fungus tissue only: ascocarps are usually dark and carbonaceous.

Annulatascus, Batistia, Cephalotheca, Chaetomium, Chaetosphaeria, Coniochaeta, Helminthosphaeria, Lasiosphaeria, Nitschkia, Neurospora, Sordaria. 

ORDER XYLARIALES

Amphisphaerella, Clypeosphaerella, Diatrype, Graphostroma, Hyponectria, Xylaria.

CLASS LABOULBENIOMYCETES

Mainly obligate parasites of insects, especially beetles, with distinctive non-mycelial and determinate growth pattern. With main body of the fungus, the receptacle, attached to host by basal cellular holdfast; single, simple haustorium penetrating host; receptacle varies in size and complexity, in some row of 3 cells, in others large number of cells superimposed in tiers. Lateral filamentous appendages and 1 or more sessile or stalked perithecia arise on receptacle; asci usually 4-spored; ascospores usually colorless, elongated and more or less spindle-shaped, 2-celled with large basal cell, each surrounded by a colorless envelope thickened at the lower end; ascus wall deliquesces prior to spore discharge. 

ORDER LABOULBENIALES

Laboulbenia.

LITERATURE CITED

Adl, S. M., A. G. B. Simpson, M. A. Farmer, R. A. Andersen, O. R. Anderson, J. R. Barta, S. S. Bowser, G. Brugerolle, R. A. Fensome, S. Fredericq, T. Y. James, S. Karpov, P. Kugrens, J. Krug, C. E. Lane, L. A. Lewis, J. Lodge, D. H. Lynn, D. G. Mann, R. M. McCourt, L. Mendoza, O. Moestrup, S. E. Mozley-Standridge, T. A. Nerad, C. A. Shearer, A. V. Smirnov, F. W. Spiegel, and M. F. J. R. Taylor. 2005. The new higher level classification of eukaryotes with emphasis on the taxonomy of protists. Journal of Eukaryotic Microbiology. 52(5):399-451.

Alexopoulos, C. J. and C. W. Mims. 1979. Introductory Mycology.  3rd  ed.  John Wiley and Sons. New York.

Alexopoulos, C. J., C. W. Mims, and M. Blackwell. 1996. Introductory Mycology. 4th ed., John Wiley & Sons, New York. 

Bold, H. C., C. J. Alexopoulos, and T. Delevoryas. 1987. Morphology of Plants and Fungi. 5th Edition. HarperCollins Publishers, Inc. New York.

Eriksson, O. E., ed. 2000a. Notes on ascomycete systematics. 4(2756-2939): 1-20. 

Eriksson O. E., ed. 2000b. Notes on ascomycete systematics. 5(2940-3127): 1-35. 

Eriksson O. E., H.-O. Baral, R. S. Currah, K. Hansen, C. P. Kurtzman, G. Rambold, T. and Laessøe, eds. 2001 Outline of Ascomycota - 2001. 7: 1-88.

Liu, Y. J., S. Whelen, and B. D. Hall. 1999. Phylogenetic relationships among Ascomycetes: Evidence for an RNA polymerase II subunit. Molecular Biology and Evolution. 16(12): 1799-1808. 

Lutzoni, F. F. Kauff, C.J. Cox, D. McLaughlin, G. Celio, B. Dentinger, M. Padamsee, D. Hibbett, T.Y. James, E. Baloch, M. Grube, V. Reeb, V. Hofstetter, C. Schoch, A.E. Arnold, J. Miadlikowska, J. Spatafora, D. Johnson, S. Hambleton, M. Crockett, R. Shoemaker, G, Sung, R. Lucking, T. Lumbsch, K. O’Donnell, M. Binder, P. Diederich, D. Ertz, C. Gueidan, K. Hansen, R.C. Harris, K. Hosaka, Y.W. Lim, B. Matheny, H Nishida, D. Pfister, J. Rogers, A. Rossman, I. Schmitt, H. Sipman, J. Stone, J. Sugiyama, R, Yahr, R, Vilgalys. 2004. Assembling the fungal tree of life: progress, classification, and evolution of subcellular traits. American Journal of Botany. 91(10): 1446-1480.

Margulis, L. and K. Schwartz. 1982. Five kingdoms, an illustrated guide to the phyla of life on earth. W.H. Freeman and Co.  New York. [C]

Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W.H. Freeman and Co.  New York. 

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company.  New York. 

Nishida, H. and J. Sugiyama.1994. Archiascomycetes: detection of a major new lineage within the Ascomycota. Mycoscience. 35:361-366.

Scagel, R. F., R. J. Bandoni, G. E. Rouse, W. B. Schofield, J. R. Stein, and T. M. C. Taylor. 1984. Plant Diversity, An Evolutionary Approach. Wadsworth Publishing Co. Belmont, CA.

By Jack R. Holt.  Last revised: 03/10/2013