Diversity and distribution of lichens from the monuments of Gwalior division, Madhya Pradesh with special reference to rock porosity and lichen growth

The present study reports the diversity and distribution of lichens growing on historical monuments of Gwalior division. Result revealed the occurrence of 28 lichen species belonging to 16 genera and 9 families. The members of the lichen family Physciaceae, Teloschistaceae and Verrucariaceae dominate the lichen diversity on monuments as represented by 5 species each of the families, followed by members of Peltulaceae and Lecanoraceae. Among the different growth forms, crustose exhibits their luxuriant growth, followed by squamulose and foliose on various monuments. Substrate preference for lichen colonization is apparent by occurrence of maximum diversity of lichens represented by 27 species on sandstone, followed by concrete, igneous granite, calcareous and clay represented by 7, 6, 5 and 2 species respectively. The rock porosity was calculated to measure water holding capacity and the correlation between rock porosity and lichen growth were studied which shows that the squamulose growth form lichen Endocarpon rosettum and Endocarpon subrosettum with thick medullary zone, grows on rocks having maximum water holding capacity of 43% each followed by Phylliscum indicum and Endocarpon nanum growing on rocks with 23% and 16.5% water holding capacities respectively.