BASIDIOLICHENS​

STUDY OF EXTERNAL FEATURES OF THALLUS (BASIDIOLICHENS)

Comments :-

  • The basidiolichens are tropical in distribution and are found growing upon bare soil, rocks and trees. 
  • There are only three genera of basidiolichens and out of these Cora pavonia is the best known.
  • The thallus is much lobed, internally attached to the substratum by rhizines and resembles superfically with ‘bracket fungi’.

BASIDIOLICHENS

STUDY OF INTERNAL STRUCTURE​ OF THALLUS (BASIDIOLICHENS)

Comments :-

  • As seen in a vertical cut, the thallus is differentiated into three layers-the superior layer, the algal or gonidial layer and the inferior layer. 
  • The superior layer is uppermost and consists of loose felt of more or less perpendicular hyphae. 
  • The algal layer is the middle one. It is made of algal cells (Chroococcus species) intermixed with loose hyphae. 
  • The inferior layer is the lowermost which is a dense felt of hyphae running in all directions. 
  • The lowest surface bears concentric outgrowths of more or less perpendicular hyphae. 
  • Each outgrowth is known as sub-hymenium and its lower face bears a palisade-like layer of basidia. 
  • Each basidium bears four terminal sterigmata with basidiospores. 
  • Basidiospores are thus shed from the underside of the lichen. These on contact with alga form a lichen.

BASIDIOLICHENS

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