345 



MY GARDEN. 



Creeping over the ground, immediately after the frost has passed 

 away, we have a green mossy-looking growth (Lyngbya muralis), 

 composed of very delicate fibres, which when magnified loo diameters 

 (fig. 794) appears simply to have transverse septa dividing the tubes, 

 but when further magnified to 300 diameters (fig. 795) discloses its 

 structure at every cell. 



Fig. 794. — Lyngbya muralis, 

 X TOO diam. 



Fig. 796. — Nostoc commune. 



Fig. 795. — Ditto, x 300 diam. 



Later in the season, upon the gravel-paths after rain, a curious 

 plant, called Nostoc commune, appears (fig. 796). It resembles a dark 

 green jelly, and has a structure under the microscope which the 

 engraving very well shows. 



But the more important confervse live in the water, and exercise 

 an influence upon the state of the river. Early in spring the Conferva 

 rivularis (fig. 797) appears. When seen by the naked eye, it has delicate 



Fig. 797. — Conferva, rivularis, nat. size. 



Fig. 798. — Conferva rivularis, x loo diam. 



Fig. 799. — Conferva, x so diam. 



long wavy threads ; but when magnified 100 diameters (fig. 798), every 

 thread is seen to be jointed, and has a cell in the interior of every 

 division. The coarse conferva in fig. 799 shows well how fine the 

 filaments of C. rivularis are when compared with other species. 



