52 EASY LESSONS IN VEGETABLE BIOLOGY. 



the anthers, or male organs, of flowering plants. The 

 cells of each antheridium contain little swimming 

 bodies called antherozoids, (living anthers.) (Fig. 22.) 



These coiled up anther- 

 ozoids twist and turn about 

 until they escape from the 

 cell and swim in the fluid 

 by means of their two cilia. 

 They find their way to the 

 spore-cases, and by coales- 

 cence form the oospore, (the 

 egg-spore, or embryo,) from 

 which the future plant is 

 Fig. 22. derived. When we consider 



the power of motion in these organs and others simi- 

 lar to them, we are obliged to admit that sharp lines 

 of distinction between plants and animals are impos- 

 sible in these apparently simple forms. The growing 

 spore of the stoneworts gives off two filaments, one 

 of which serves as a temporary root, while a cell in 

 the other produces a group of lateral projections from 

 which the young plant springs. This temporary 

 structure is termed the pro-embryo, and something 

 similar to this is common to all the Acrogens. 



2. Ferns form another family of Acrogens, or sum- 

 mit-growers. Their various species are admired for 

 their beautiful fronds, often improperly called leaves, 

 and books of collectors often grace the parlor table. 



