90 CHLOROSPERME^G, OR GREEN SEA-WEEDS. 



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 ex- 

 tremity. 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 JZnteromorphce succeed Ulvce, distinguished from 

 Enter omorplice merely by being flat, instead of tubular. 

 The beautiful lettuce-like plaited leaves found in tide- 

 pools, belong to plants of this genus, the commonest 

 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 beauti- 

 ful, equally common, and more generally collected 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 ( Viva latissima), but it is of a still more delicate 

 substance, consisting of a perfectly transparent and 

 very thin membrane, elegantly dotted with closely-set 

 grains, to which it owes its colour. When these grains 

 are in perfection they are of a dark violet-purple ; and 



