GREEN-COLOURED ALGJ1. 133 



on the Devonshire coast as well as on the coast of 

 Ireland. The colour is a purplish green, and it 

 is well known as the Irish moss, which, when 

 boiled, produces a nutritious jelly. Of the class 

 of which we have thus referred to one or two 

 examples there is a large number of species. 



It now remains that we notice a few of the 

 series termed Chlorospermece. 



These plants are the least beautiful and in- 

 teresting of the sea-weeds. The most common 

 of them belong to the order Confervas. Some of 

 these are to be found on every sea-shore, covering 

 the stones in great profusion, and rendering them 

 very slippery. The Ulva latissima or green 

 sloke, the colour of which is a full green, and of 

 which the fronds are broadly egg-shaped or oblong 

 and variously cleft and waved ; the Porphyra laci- 

 niata, or cleft porphyra, laver or sloke, of a rich 

 purple colour, a species sometimes boiled and 

 used at table, and several other species, are com- 

 prehended in this class. 



Of the three series referred to a large number 

 of species present themselves to the lovers of 

 marine botany, and all of them will be found 

 worthy of notice either from their appearance, 

 their structure, or the purposes to which they are 

 applicable. To some peculiarities in their phy- 

 siology we shall in a succeeding chapter direct 

 our readers' attention. 



K. 3 



