8 SCIENCE PRIMERS. [n. 



independent plantlet (embryo). The Flowerless plants 

 (ferns, mosses, seaweeds, &c.) have no such flowers, 

 nor such seeds : instead of seeds they have spores 

 which contain no plantlet, but themselves grow into 

 new individuals. 



Plants purify the air that is being habitually 

 rendered unfit to breathe by animals having already 

 breathed it. They provide the animal kingdom with 

 food, and often with shelter. They protect the 

 surface of the earth from being too much scorched 

 by the sun's rays by day, and too rapidly cooled by 

 radiation at night. They prevent the too rapid 

 evaporation of the rain-fall; and they supply man 

 with fuel, medicine, and many materials for arts and 

 manufactures. 



II. GENERAL CHARACTERS OF FLOWERING 

 PLANTS. 



1. The Vegetable Kingdom as stated above pre- 

 sents two quite distinct Sub-kingdoms, which the most 

 superficial observer rarely confounds : that of flower- 

 ing plants, to which trees, shrubs, and herbs belong; 

 and flowerless plants, such as ferns, mosses, sea- 

 weeds, lichens, and fungi. 



The pupil is recommended to begin with the 

 flowering plants, not only because the two sub- 

 kingdoms are so different that they cannot be studied 

 together advantageously by a beginner in Botany, but 

 because the flowerless plants require for their study 

 high magnifying powers of the microscope and great 

 skill in using them. 



2. Flowering plants present the following organs or 



