50 AQUATIC MICROSCOPY FOR BEGINNERS. 



feet long, yet it always looks soft and feathery. The 

 leaves are numerous, and each set is arranged in a 

 circle around the stem; they are in "whorls, " as the 

 botanist calls the arrangement. One such whorl is 

 shown in Fig. 8. Kve dissected leaves are there 

 drawn, but whorls sometimes occur with three or four, 

 the number helping to distinguish- the species, of 

 which there are several, all of them closely resembling 

 one another when in the water. The parts of the leaf 

 are fine, soft, and hair-like, those nearest the stem of 

 the plant being the longest. They are numerous and 

 close together, thus giving the floating streamers their 

 peculiar thick and soft appearance, and making them 

 an excellent place for the microscopist to explore. 



To compare with Fig.- 8 a feathery plant which the 

 collector does not know, select a circle of leaves, cut 

 the stem close above and below it, and after .floating 

 the separated whorl in a saucer as already directed, or' 

 spreading it out on white paper, compare its leaves 

 with those figured. They vary in size in different 

 parts of the plant, the uppermost being smallest and 

 youngest, the lower the oldest and largest. 



There is another rather common aquatic plant called 

 Proserpindca, or "mermaid-weed," which so closely re- 

 sembles Myriophyllum when in the water that it has 

 often been mistaken for it. To make such an error is 

 of no great consequence, unless it should lead the ob- 

 server to imagine, as it once did the writer, that he 

 has found a rare species of Myriophyllum. Yet it is 

 always pleasant, if nothing else, to feel sure, and it is 

 more than pleasant to have a reputation for accurate 

 observation. Proserpinaca, however, is as useful a trap 

 as Myriophyllum from which it can be easily distin- 



