244 FIRST FORMS OF VEGETATION. . 
Skye, Arran, and on the west coast of Scotland, 
where it is used by the Highlanders, when rubbed 
between their hands in water, as a paste with 
which to purge their calves. Attached to aquatic 
plants, and stones at the bottom of ponds, and 
in the shallow margins of still lakes, may often be 
seen a very curious little plant belonging to this 
tribe called Rivularia angulosa. It closely re- 
sembles green-gage plums in size, shape, and ap- 
pearance, and is always found associated in little 
colonies. It isa simple, roundish mass of gelatine, 
filled internally with beautiful beaded filaments. 
The least touch detaches it from its growing-place, 
when it rises to the surface of the water with the 
velocity of an air-bubble, and refuses to sink again, 
floating freely about. The whole genus Rivularia 
is composed of exceedingly curious plants, most 
of them occurring in shallow rivulets, and alpine 
cascades and streamlets, where they adhere, in the 
form of glossy bead-like dots of a dark-olive col- 
our, to the stones of the bottom, generally prefer- 
ring pure white quartz and glittering mica schist. 
The whole plant is not larger than a pin’s-head, or 
a small pea; but it sometimes spreads widely in 
favourable situations, covering all the stones in the 
bed of a streamlet, and giving them an appearance, 
as the little, bustling, transparent waves roll and 
sparkle over them, as if they were full of eyes. 
