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trasting with the green fields. Flat roofs are in like manner coloured after rain 
by the Protococcus pluvialis. 
In the Arctic regions green and brown slimes are mentioned by Professor 
Nordenskjéld as covering hundreds of thousands of square miles of water, and this 
slime when examined was found to be made up of various species of minute 
cellular vegetable organisms. In like manner it is stated by Dr. Hooker in his 
“Botany of the Antarctic Voyage,” that the waters and ice of the South Polar 
Ocean abound with microscopic vegetation in such countless myriads as to stain 
the berg and pack ice and the base of the great Victoria barrier itself wherever 
exposed to the swell of the sea, of a brown colour, as if the Polar waters were 
charged with oxide of iron. So the Red Sea produces a local Algal that has been 
noticed to redden its surface to such an extent that vessels have taken days to pass 
through it, and it has been suggested that the Red Sea has thus received an 
appropriate name. 
Rocks are also coloured and darkened by various minute cellular organisms, 
either Diatoms or belonging to the Desmidiacec, and names in accordance with the 
hues displayed are given to such localities. There is in Worcestershire a range 
of rocks on the banks of the Severn called Blackstone Rocks, though in reality 
formed of new red sandstone. But the surface of these rocks is blackened to a 
great extent by a minute cellular Algal which gives them the appearance of having 
been blackened by fires. There is a curious byssoid substance of a golden colour, 
-known as Chroélepus aureus, that burnishes old stone crosses, damp rocks, and 
occasionally trunks of trees. When once wandering in Wales, I came upon a 
plantation of old Larches, whose trunks were so covered with this bright-hued 
plant that when the sun shone upon them they appeared like pillars of gold. 
But what shall I say of the Fungi? They certainly contribute to the 
colouring of the landscape, though in a subservient degree, because it is only in 
autumn that they make themselves visible in any number. Polyporus and some 
other genera of a persistent nature show themselves indeed at other times, and in 
botanical rambles I have been often struck with the appearance of large masses of 
Polyporus sulfureus, very bright in colour—often on yew trees; and of Polyporus 
squamosus, on the Ash. Among old trees in parks and forest places, various 
Polypovt often make a peculiar feature, fringing decaying branches; and in the 
New Forest, and in Wales, I have seen old birches with such a number of the 
cake-like P. betulina upon them, that it might be supposed they were laden with 
fruit. On rotting boles the black glue-like Bulgaria inquinans, when in clusters, 
is very remarkable in shady silvern retreats found out by the fungologist. 
But the Agarics and Boleti, where they are numerous and freshly sprung up, 
give a colorific featnre to the ground as soon as the mists of autumn begin to 
prevail, justifying Tennyson’s remark as to Fungi— 
Which in autumn-tide do star 
The black earth with brilliance rare. 
A friend of mine, with whom I was walking through a wood last year, and 
who had paid little or no attention to Funguses, was perfectly astonished at the 
scarlet hues of the numerous fly-Agarics (Amanita muscarius) that presented them- 
