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British Chlorosperms are chiefly composed of Ulvae and Entero- 

 morphae, whose forms vary with so little order, that it becomes 

 difficult, and, in some instances, hopeless, to attempt to classify the 

 varieties. The Enteromorphae are the first to make their appearance 

 about high-water mark, covering loose boulders or smooth rocks with 

 a slippery vesture of bright green, or filling the shallow tide-pools with 

 grassy fronds. These plants consist of tubular membranes, simple or 

 branched, appearing to the naked eye like fine green silk, and showing 

 to the microscope a surface composed of minute cells, full of granules. 

 The commonest species near high-water mark is E. compressa, which 

 commences of a very stunted size, and with thread-like branches, if 

 exposed to the air, and gradually acquires length and breadth as it 

 grows in deeper water. When fully developed, it has a frond divided 

 nearly to the root into many long, subsimple branches, which bear a 

 second or third series, all of them much attenuated at their insertion, 

 and more or less distended at the extremity. The diameter of the 

 tube varies extremely, and the broader and simpler individuals are 

 only to be known from E. intestinalis, by their being branched ; the 

 tube in the latter species being absolutely simple. To the Entero- 

 morphas succeed Ulvae, distinguished from Enteromorphae merely by 

 being flat, instead of tubular. The beautiful lettuce-like plaited 

 leaves found in tide-pools, belong to plants of this genus, the com- 

 monest species of which is U. latissima. It has a very broad, more 

 or less ovate, plaited leaf, of a brilliant green, and remarkably glossy, 

 when in perfection reflecting glaucous tints, if seen through clear sea- 

 water, and is certainly a very ornamental species. It is sometimes 

 brought to table as a laver, or marine sauce, but it is much inferior in 

 flavour to the purple laver (Porphyra laciniata), a plant of the same 

 family, equally beautiful, equally common, and more generally col- 

 lected for food. The purple laver grows on exposed rocks near low- 

 water mark, and though called purple, assumes at different seasons of 

 the year different shades of colour, according to its age. In form it 

 resembles the green laver (Ulva latissima), but is of a still more deli- 

 cate substance, consisting of a perfectly transparent and very thin 

 membrane, elegantly dotted with closely set grams, to which it owes 

 its colour. When these grains are in perfection, they are of a dark 

 violet-purple ; and this is the case in winter and early spring, when 

 the plant is collected for the table. Later in the year the fronds are of 

 stunted size, and more or less olivaceous colour, and much less suit- 

 able for gathering. The plant appears to be of very rapid growth and 

 decay, a few weeks sufficing for its full development. Like may fugi- 



