GRASS -WRACK. 



411 



name of "Mattress Grass-wrack", because it is much used 

 in more nortlierly latitudes for upholstery. In Venice it 

 has been employed for ages to pack the glass ware and 

 thus obtained the name of Alga Vitrcfrioruni. Posidojiia 

 oceanica is also used in Italy, here and there, for packing, 

 and in North Africa they thatch roofs with it. Both 

 plants belong to the Pond weeds or Potamogetonaceae, 

 and are monocotyledonous Phanerogams. Ligurian Grass- 

 wrack grows at a far greater depth than the Zostera. 

 In shallow water its leaves ma\' be seen waving to and 

 fro like grass in our meadows when stirred by the wind. 

 In the bay between v the old town 

 of Antibes and the 

 l^rojecting Cap, Posi- 

 donia grows in such 

 quantities that the shore 

 is heaped up high 



^'ibtiyiiiiiii Tint 



