136 FOOTNOTES FROM 



Some species grow in moist, damp places, where they 

 form a thin glossy-black pellicle of indefinite extent over 

 the ground, strongly resembling, when dry, a piece of 

 black satin (Fig. 19). Others are found in ditches and 

 ponds; a third species spreads extensively over damp 

 walls in autumn and winter, a peculiar variety covering 

 the damp walls in the inside of some Suffolk churches 

 with bright sky-blue mould-like patches ; a fourth is 

 often found on rotten timber, and trunks of aged trees 

 where rain-water trickles down. They may be found 

 parasitic upon mosses in rapid streams, and forming 

 thick glossy strata of a dull-brown or vivid-green colour, 

 at the bottom of clear, tranquil linns, wherever a film of 

 soil is allowed to accumulate upon the naked slippery 

 rocks. They are found in sulphur springs, forming pale 

 yellow continuous tufts wherever the water retains sen- 

 sible sulphureous qualities, as if the hepatic gas were 

 necessary to their growth ; and in the celebrated warm 

 waters of Bath, a peculiar species grows in broad velvet- 

 like patches of a dark-green colour. Their vitality is so 

 great that they are capable of enduring the extremes of 

 heat and cold, for they have been found on fragments of 

 ice in Melville Island, where the temperature is consider- 

 ably below zero; and they have been found growing in 

 thermal springs in different parts of the globe, where the 

 heat is sometimes so great that the inhabitants of the 

 surrounding districts dress their food over them, and use 

 them for other economic purposes instead of fire. 



A magnificent species forms thick woolly fleeces of a 

 deep red colour, in the central and western districts of 

 India, occurring in great profusion in the hot/sweltering 



