OP SOUTH AUSTRALIA. 
9 
Different weeds will be found on mudflats and on rocky bottoms. On 
sandy beaches weeds cannot obtain a sufficiently permanent footing to be 
able to grow. The mudflats are often covered with the 4 ‘sea grasses'’ 
Posidonia and Zostera. These should be searched for true seaweeds which 
grow upon them. 
Weeds growing on the rocks and exposed at low tide are often eaten 
down by mollusca, and are stumpy and bushy, and so abnormal. Such 
plants, for instance stumps of Sargassa, are not worth collecting. Plants 
should be fresh and well grown, and the complete plant gathered with 
its attachment. 
Preservation. — Algae may be preserved as dry mounted specimens or 
kept in formalin in jars. Dry mounts keep their colour and structure for 
an apparently indefinite period, provided that they are not constantly 
exposed to light. Harvey’s plants gathered and mounted 80 years ago are 
unaltered at the present time. Portions can usually be moistened and 
removed for examination under the microscope after having been kept dry 
for years. But for investigation on the development, especially of the 
reproductive organs, it is essential to harden fresh growing material by 
fixing agents and then to preserve in formalin or alcohol. 
To mount weeds place in flat basins containing fresh water. All washing 
and cleansing from sand and foreign growths should be accomplished 
previously with sea water. Cartridge paper, cut to standard sizes, is then 
placed beneath the weed in the water; the plant is floated out over the 
paper to display it as naturally as possible. The paper is then gently 
raised for the water to run off, and then laid on a sloping board to drain. 
Drying is effected in a press. Newspapers are quite good for the pur- 
pose, but a special “drying paper” can be obtained from some wholesale 
stationers. Blotting paper is useless. A sheet, doubled if of newspaper, 
is laid down, and the drained mount laid on it, and over this again a 
sheet of butter muslin. A second layer of newspaper, a second mount, a 
second muslin; more triple layers until the pile is built up. On the pile 
a board is laid, and on this weights of some sort are placed so as to apply 
an even pressure. The weight should be steady but not so as to crush the 
specimens. A full-sized sheet of cartridge, when folded into four, gives a 
convenient size for the larger mounts, about 15in. by llin. One of these 
quarter sheets folded again gives an intermediate size, which is suitable 
for most specimens; and this folded again serves for the small plants. 
Most marine algae when placed in fresh water exude a mucilage by 
which they adhere to the cartridge paper and less closely to the muslin. 
The papers should be changed after 12 hours, dry papers and muslins 
replacing the wet. Further changes should be made until the plants are 
dried. The muslins peel off readily, and the plant remains fixed to the 
cartridge. 
