Discomycetes

DISCOMYCETES

SRIVANI GAYATHRI

Contents

• Introduction

• Habitat

• Classification

• Apothecium Structure

• Conclusion

• Reference

Introduction

A vast group-2,720 genera and 28,650 species.

This includes the members with cup-shaped/

saucer-shaped, some are club-shaped,

mushroom-like, sponge-like etc..

These produce fructification called

Apothecium, is the main feature of

identification. Discomycetes are Ascomycetes with

apothecium.

Habitat

Most of the members are saprobes in nature

but few are parasites, cause serious

diseases of economic plants. Some are

coprophillus and also constitute lichens.

For instance., Sclerotinia fruticola- Brown rot

in pear

Quercus -Mycorrhizae

forming

Classification

Discomycetes- grossly classified- based on

the

presence/ absence of Operculum.

• Inoperculate

• Operculate

Ainsworth divided Discomycetes into 6

orders viz.,

• Pezizales

• Tuberales

• Rhytismatales

• Ostropales

• Helitiales

• Cyttariales

Each order contains some families and few

genus

Pezizales

• Largest of operculate Discomycetes usually

saprobes on soil, dead wood, plant debris/

humus

• Apothecia may be fleshy/ brittle/ leathery

/ rarely gelatinous

• The asci are arranged in a distinct

hymenium with paraphyses

• Edible- Morchella esculenta

PEZIZA BADIA PEZIZA CEREA

Tuberales

• Commonly called Truffles

• Used as food, in liquor making, for scenting

tobacco, in perfumes etc

• The ascomata remains closed and are fleshy

to leathery/ globose with a hymenium

• Mycorrhizae- Quercus

TUBER RUFUM

Rhytismatales(Phacidiales)

• Saprobes/ plant

parasites on leaves and

wood

• Produce characteristic

apothecoid ascocarps

immersed in a stroma/

host tissue

• Asci are inoperculate

and apically thick Rhytisma

Ostropales

• Saprobes / parasites of herbaceous/ woody

stem

• Crustose lichen formation

• Asci- long and cylindrical

• Young ascal apex, thick, traversed by a pore

through which ascospores are discharged

Crustose lichen with Apothecia

Helotiales

• Inoperculate forms

• Saprobes on soil, dead wood, dung and

parasites that cause plant diseases

(Sclerotinia spp.)

• Ascocarps may be superficial or immersed

in substratum

Cyttariales

• Large ascomata-

spherical to pyriform

• Asci are operculate

• Cushion of epiplasm

remains between

ascospores

CYTTARIA ESPINOSAE

Apothecium

• It is divided into 3 anatomical regions

- Hymenium

- Subhymenium

- Excipulum

• Hymenium is made of cylindrical/ club-

shaped asci and paraphyses in a palisade

layer

• Subhymenium is a zone of tissue that give

give rise to asci and paraphyses

• Excipulum- 2 parts- ectal and medullary

Stages of Ascospore formation

Conclusion

The members commonly produce asci within

apothecium, may be operculate/

inoperculate. Morchellaceae under Pezizales

has the members like mushrooms, which

resemble the mushrooms.

Reference

• R.S. MEHROTRA & K.R. ANEJA (2010)

AN INTRODUCTION TO MYCOLOGY

Pg no. 363-389

New Age International (p) Ltd., Publishers

• JOHN WEBSTER, 1970,

Introduction to fungi, pg no. 246-272.

Cambridge university press

•http://www.symbiology.com/pdf/Gargas7

.pdf