36 THE WEEDS OF NEW SOUTH WALES. 



valuable waterways for the shipment of the produce of the farms in the 

 vicinity had become completely blocked, and navigation entirely prevented 

 or rendered distinctly dangerous to the steamboats and launches that plied 

 upon the rivers. At times the hyacinth has even been responsible for sus- 

 pending ferry traffic at Grafton, and on the Lower Clarence punt-wires have 

 often been broken. In many of the " clumps " of hyacinth, which reached a 

 quarter of an acre in extent, logs were to be found, and some idea of their 

 danger may be estimated when it is remembered that these were being carried 

 down with the current at the rate of from 4 to 6 knots an hour. 



Efforts were made on several occasions to get rid of the pest, and at Swan 

 Creek alone a sum of something like 800 was expended by the late Sir 

 John See in dragging the hyacinth out of the stream. This work was never 

 completed, however, and in a few years the whole of the creek was again 

 covered. 



The hyacinth is not confined to this State alone. In Florida the pest 

 has assumed gigantic proportions, as the following extract from Bulletin 

 No. 18 of the United States Department of Agriculture (Division of Botany) 

 shows : 



Damage caused by the Water Hyacinth. 



That the water hyacinth is becoming a serious menace to navigation in the 

 St. John's River (Florida) is unquestionably true. Small boats with screw 

 propellers find it impossible to penetrate a very large mass of the plants, as 

 they lack the necessary power, and the plants soon become entangled in the 

 screw, and prevent it from revolving. Parting the plant with boat-hooks, &c., 

 is very slow and tedious. Paddle-wheel steamers are able to penetrate the 

 extensive masses of the plants much better, but are generally hindered and 

 frequently entirely blocked. When a large steamer, going at full speed, strikes 

 a bank of the hyacinth, it comes almost to a standstill. In sidewheel steamers 

 the plants collect between the wheel and bulkheads, packing it so solidly that it 

 is often almost impossible to reverse the engine. This necessitates caution in 

 approaching the landings. Steamers with low-pressure engines are troubled by 

 the clogging of the injector pipes, so that sufficient water cannot be secured for 

 the condensers. In the case of some boats, the obstruction is occasionally 

 removed by blowing steam through the injector-pipe. This process, however, 

 is rather dangerous, as the injector-pipes and condensers are not constructed 

 with a view to having heavy pressure applied from within. Floating logs 

 frequently lie concealed in the masses of the plants and form a serious danger 

 to navigation. Several boats have already been injured to some extent by 

 striking such obstructions. 



The hyacinth is a pretty aquatic, and thrives in water in a warm climate. 

 The foliage is killed by frosts in the winter. It seeds profusely, and it is 

 mainly on this account that the plant is difficult to eradicate. At the base 

 of the leaf stalk is a large bulbous-looking development, which is composed 

 of numerous air-cells, which act as floats and support the plant in the water. 

 The roots penetrate to a depth of from 2 to 4 feet, and it thrives just as 

 well in 40 feet of water as in only a few feet. 



The seed as it ripens falls between the leaves of the parent plant, and 

 coming in contact with the water germinates and grows. As the older plants 

 mature they are gradually forced below the surface of the water by the 

 younger generation, and as they die they accumulate at the bottom. In 

 shallow watercourses or lagoons it is only a matter of a few years when they 

 will be filled up with a dense mass of decomposing organic matter. 



