2 V J I 'SCIENCE PRIMERS. [i. 



of in r ancy, ; ihatur;fy, arid death ; they also feed, grow, 

 and multiply. Unlike the higher animals, during the 

 ordinary processes of growth (with the exception of 

 germination and flowering) they have no proper heat, 

 not being warmer than the air or water in which they 

 live. 



Duration of Plant-life. Some plants have 

 limited lives, flowering but once and dying soon after; 

 others have unlimited lives, throughout which they 

 flower periodically. Plants with limited lives are: i. 

 Annuals, which live but for one year or season, as 

 wheat, peas, &c. ; 2. Biennials which live for two 

 years, as the cabbage, turnip, foxglove, &c. ; and 3. 

 plants which grow for many years without flowering 

 (for example many palms), flower but once, and 

 then die. Those with unlimited lives are Perennials, 

 and may be either trees and shrubs which, like the 

 oak and hawthorn, have stems and branches increasing 

 in size from year to year ; or herbs like the primrose 

 and snowdrop, having underground root-like stems 

 which annually send up leaves or branches that die 

 off in the same year. 



Distribution of Plants. Plants are found on 

 nearly all parts of the surface of the globe, but no 

 two countries have all their plants alike. They are 

 found in the greatest luxuriance and variety in hot 

 and damp climates. They are not found in the 

 very coldest or very dryest regions, nor at very great 

 depths in lakes, or the ocean. As a rule, they 

 diminish in size, as well as in number of kinds in pro- 

 ceeding from the tropics to the frigid zones ; as regards 

 size there are exceptions, as the gum-trees of South 

 Australia and the wellingtonia of California, which 



