POLYPORUS
(BRACKET FUNGUS)

CLASSIFICATION OF POLYPORUS (BRACKET FUNGUS)

Kingdom :- Mycota

Division :- Eumycota

Sub-division :- Basidiomycotina

Class :- Hymenomycetes

Sub-Class :- Holobasidiomycetidae

Order :- Polyporales

Family :- Polyporaceae

Genus :- Polyporus

Polyporus (Bracket fungi) are common on tree trunks or on wood in damp forests.

STUDY OF HOSTS AND DISEASES

COMMENTS :-

  • Many species of the genus are destructive parasites and cause disease in forest and other shade trees. Many others grow on lumber and destroy it.
  • P. sulphureus (sulphur mushroom) causes Wood rot of oaks (Quercus sp.; fam. Fagaceae). 
  • P. squamosus causes a serious Heart rot in elms (Ulmus sp.; fam. Ulmaceae) and other trees.
  • P. versicolour grows on various woods and is known as Wood rotter. 
  • P.betulinus is very common on birch (Betula sp.; fam. Betulaceae).

Polyporus. Basidiocarp growing on wood.

VEGETATIVE STRUCTURE​

COMMENTS :- 

  • The mycelium is well developed, branched and septate.
  • Generally the mycelium grows within and below the bark but in case of severe attacks, it completely invests the central wood cylinder.

Polyporus. Basidiocarp growing on wood.

STUDY OF BASIDIOCARP, GILLS, BASIDIA AND BASIDIOSPORES​

COMMENTS :-

  • The mycelium (dikaryotic) forms a more or less flat fruting body, the basidiocarp. 
  • The basidiocarp is characteristically shelf-like, shortly stalked and arises from the tree trunks.
  • It is leathery, corky or woody, whitish or slightly greyish or brownish in colour. 
  • The upper surface is generally smooth, sometimes rough, often undulating, while the lower surface is porous. In some species the upper surface is distinctly striated. 
  • The section of basidiocarp shows an outer context, trama, pores and hymenium. 
  • The context is the outer fibrous part made up of thick walled hyphae. 
  • The trama is a loose mass of much branched, septate and anastomosing hyphae. 
  • The pores or tubes extend from below the context to the lower surface. 
  • The hymenium is made up of a distinct layer of basidia, lining each pore or tube.
  • The basidia are club-shaped, somewhat larger than the steile cells of the hymenium and project slightly into the cavity of the pore.
  • Each basidium has four short sterigmata at its free end, terminating into a basidiospore each. 
  • The large number of basidiospores are discharged in the pore.
  • Each basidiospore is small, oval and is uninucleate. 
  • The basidiospore on germination gives rise to the mycelium (monokaryotic).

Polyporus. Basidiocarp in section (a part only)

IDENTIFICATION

  • KINGDOM – Mycota
    1. Chlorophyll absent
    2. Reserve food glycogen
    3. Cell wall of fungal cellulose.
  • DIVISION Eumycota
    1. A definite cell wall present.
  • SUB-DIVISION :- Basidiomycotina
    1. Mycelium septate.
    2.  Characteistic reproductive body, basidium.
    3.  Basidiospores usually four, produced exogenously.
  • CLASS :- Hymenomycetes
    1. Basidiocarps usually well developed,
    2. Mostly saprobic.
  • SUB-CLASS :- Holobasidiomycetidae
    1. Basidia club-shaped and non septate.
  • ORDER Polyporales
    1. Texture of basidiocarp not soft and putrescent.
  • FAMILY Polyporaceae
    1. Basidia line the inner surface of the pore or tube.
    2. Tubes or pores, generally deep.
  • GENUS Polyporus
    1. Bracket or shelf-like shape,
    2. Basidiocarp grow from wood.
    3. Spores round, somewhat radially elongated.
    4. Context always white or light coloured.

REFERENCES

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