THE PAGE OF NATURE. 161 



become the common envelope of the whole mass. The 

 plant is propagated by the division of these threads into 

 their individual joints, which burst through the common 

 jelly, and become dispersed in the water, where they are 

 endowed with spontaneous motion, enabling them to con- 

 tend against currents. "These fragmentary threads," 

 says Berkeley, " divide longitudinally and transversely, 

 at last constituting a bundle of new threads, which 

 gradually, by increase of the gelatinous or filamentous 

 elements, assume the normal form of the species." 



Another allied species is the mountain dulse_of the 

 Scotch (Palmetto, montana), occurring very frequently in 

 patches of a deep but dull purple colour, in moist, stony 

 places, on the mountains of Skye, Arran, and on the 

 west coast of Scotland, where it is used by the High- 

 landers, when rubbed between their hands in water, as a 

 paste with which to purge their calves. Attached to 

 aquatic plants, and the 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 Rivulana angulosa. It closely resembles green- 

 gage plums in size, shape, and appearance, and is 

 always found associated in little colonies. It is a 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 gloesy, 

 L 



