182 . BOTANY. 



thicker-walled and constitute the proper spore-fruit. The 

 latter soon drops o£E and falls to the bottom of the water, 

 where it remains at rest for a time. 



380. The spore-fruit of the Stoneworts contains, thus, 

 but one spore. This in germination sends out a jointed 

 filament, which eventually gives rise to a branching plant 

 again (Fig. 99). 



381. Two orders (NttelleoB and Charece) may be sepa- 

 rated in this class. The principal genus of the first is Ni- 

 tella, and of the latter Chara; each contains a dozen or 

 more widely distributed species in this country. 



Practical Studies. — (o) Search the sandy margins of ponds, lakes, 

 and slow streams for Stoneworts. They are generally found in water 

 from a few centimetres to one or two metres in depth. Preserve 

 such specimens temporarily in water which is frequently changed, 

 but for future use preserve in alcoliol. 



(6) Mount carefully a considerable portion of a plant, and examine 

 its sti'ucture under a low power. Note that in some species the stem 

 (and leaves) is composed of a row of large cells surrounded by a coat 

 of smaller ones. Look for the rapid movement of protoplasm which 

 Is so marked in these plants. 



(c) Mount several spore-fruits in various stages of development. 

 Note the covering layer of spirally coiled cells surrounding the car- 

 pogone (in young specimens) or the spore (in older specimens). 



(d) Mount several full grown antherids. Carefully crush them and 

 look for antherozoids, which are produced in chains of cells. 



(e) Preserve the aquatic carpophytes by floating out of water as 

 described on page 129 (j'). In Classes III and IV the fleshy species 

 are best preserved in alcohol, while most of the remaining ones may 

 be pressed and mounted very nearly as if they were ordinary flower- 

 ing plants. 



